diff --git a/accessible/jsat/AccessFu.jsm b/accessible/jsat/AccessFu.jsm
index 4cfbfc2fa3..e0d8ecb493 100644
--- a/accessible/jsat/AccessFu.jsm
+++ b/accessible/jsat/AccessFu.jsm
@@ -340,9 +340,9 @@ this.AccessFu = { // jshint ignore:line
       case 'remote-browser-shown':
       case 'inprocess-browser-shown':
       {
-        // Ignore notifications that aren't from a BrowserOrApp
+        // Ignore notifications that aren't from a Browser
         let frameLoader = aSubject.QueryInterface(Ci.nsIFrameLoader);
-        if (!frameLoader.ownerIsMozBrowserOrAppFrame) {
+        if (!frameLoader.ownerIsMozBrowserFrame) {
           return;
         }
         this._handleMessageManager(frameLoader.messageManager);
diff --git a/caps/BasePrincipal.cpp b/caps/BasePrincipal.cpp
index ade5b4e2e0..78b09bb249 100644
--- a/caps/BasePrincipal.cpp
+++ b/caps/BasePrincipal.cpp
@@ -624,13 +624,8 @@ BasePrincipal::GetOriginSuffix(nsACString& aOriginAttributes)
 NS_IMETHODIMP
 BasePrincipal::GetAppStatus(uint16_t* aAppStatus)
 {
-  if (AppId() == nsIScriptSecurityManager::UNKNOWN_APP_ID) {
-    NS_WARNING("Asking for app status on a principal with an unknown app id");
-    *aAppStatus = nsIPrincipal::APP_STATUS_NOT_INSTALLED;
-    return NS_OK;
-  }
-
-  *aAppStatus = nsScriptSecurityManager::AppStatusForPrincipal(this);
+  // TODO: Remove GetAppStatus.
+  *aAppStatus = nsIPrincipal::APP_STATUS_NOT_INSTALLED;
   return NS_OK;
 }
 
diff --git a/caps/nsIPrincipal.idl b/caps/nsIPrincipal.idl
index 03f293f7b2..f197021caa 100644
--- a/caps/nsIPrincipal.idl
+++ b/caps/nsIPrincipal.idl
@@ -303,15 +303,6 @@ interface nsIPrincipal : nsISerializable
      */
     [infallible] readonly attribute unsigned long privateBrowsingId;
 
-    /**
-     * Returns true iff the principal is inside an isolated mozbrowser element.
-     * <iframe mozbrowser mozapp> and <xul:browser> are not considered to be
-     * mozbrowser elements.  <iframe mozbrowser noisolation> does not count as
-     * isolated since isolation is disabled.  Isolation can only be disabled if
-     * the containing document is chrome.
-     */
-    [infallible] readonly attribute boolean isInIsolatedMozBrowserElement;
-
     /**
      * Returns true if this principal has an unknown appId. This shouldn't
      * generally be used. We only expose it due to not providing the correct
diff --git a/caps/nsPrincipal.cpp b/caps/nsPrincipal.cpp
index c9e66fef7a..169ee0cb8c 100644
--- a/caps/nsPrincipal.cpp
+++ b/caps/nsPrincipal.cpp
@@ -31,8 +31,6 @@
 #include "mozilla/Preferences.h"
 #include "mozilla/HashFunctions.h"
 
-#include "nsIAppsService.h"
-
 using namespace mozilla;
 
 static bool gCodeBasePrincipalSupport = false;
diff --git a/caps/nsScriptSecurityManager.cpp b/caps/nsScriptSecurityManager.cpp
index a40240c0b2..84d0910601 100644
--- a/caps/nsScriptSecurityManager.cpp
+++ b/caps/nsScriptSecurityManager.cpp
@@ -9,7 +9,6 @@
 
 #include "xpcpublic.h"
 #include "XPCWrapper.h"
-#include "nsIAppsService.h"
 #include "nsIInputStreamChannel.h"
 #include "nsILoadContext.h"
 #include "nsIServiceManager.h"
@@ -55,7 +54,6 @@
 #include "nsIChromeRegistry.h"
 #include "nsIContentSecurityPolicy.h"
 #include "nsIAsyncVerifyRedirectCallback.h"
-#include "mozIApplication.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/dom/BindingUtils.h"
 #include "mozilla/dom/ContentParent.h"
@@ -240,68 +238,6 @@ nsScriptSecurityManager::SecurityHashURI(nsIURI* aURI)
     return NS_SecurityHashURI(aURI);
 }
 
-uint16_t
-nsScriptSecurityManager::AppStatusForPrincipal(nsIPrincipal *aPrin)
-{
-    uint32_t appId = aPrin->GetAppId();
-
-    // After bug 1238160, the principal no longer knows how to answer "is this a
-    // browser element", which is really what this code path wants. Currently,
-    // desktop is the only platform where we intend to disable isolation on a
-    // browser frame, so non-desktop should be able to assume that
-    // inIsolatedMozBrowser is true for all mozbrowser frames.  Additionally,
-    // apps are no longer used on desktop, so appId is always NO_APP_ID.  We use
-    // a release assertion in nsFrameLoader::OwnerIsIsolatedMozBrowserFrame so
-    // that platforms with apps can assume inIsolatedMozBrowser is true for all
-    // mozbrowser frames.
-    bool inIsolatedMozBrowser = aPrin->GetIsInIsolatedMozBrowserElement();
-
-    NS_WARNING_ASSERTION(
-      appId != nsIScriptSecurityManager::UNKNOWN_APP_ID,
-      "Asking for app status on a principal with an unknown app id");
-
-    // Installed apps have a valid app id (not NO_APP_ID or UNKNOWN_APP_ID)
-    // and they are not inside a mozbrowser.
-    if (appId == nsIScriptSecurityManager::NO_APP_ID ||
-        appId == nsIScriptSecurityManager::UNKNOWN_APP_ID ||
-        inIsolatedMozBrowser)
-    {
-        return nsIPrincipal::APP_STATUS_NOT_INSTALLED;
-    }
-
-    nsCOMPtr<nsIAppsService> appsService = do_GetService(APPS_SERVICE_CONTRACTID);
-    NS_ENSURE_TRUE(appsService, nsIPrincipal::APP_STATUS_NOT_INSTALLED);
-
-    nsCOMPtr<mozIApplication> app;
-    appsService->GetAppByLocalId(appId, getter_AddRefs(app));
-    NS_ENSURE_TRUE(app, nsIPrincipal::APP_STATUS_NOT_INSTALLED);
-
-    uint16_t status = nsIPrincipal::APP_STATUS_INSTALLED;
-    NS_ENSURE_SUCCESS(app->GetAppStatus(&status),
-                      nsIPrincipal::APP_STATUS_NOT_INSTALLED);
-
-    nsString appOrigin;
-    NS_ENSURE_SUCCESS(app->GetOrigin(appOrigin),
-                      nsIPrincipal::APP_STATUS_NOT_INSTALLED);
-    nsCOMPtr<nsIURI> appURI;
-    NS_ENSURE_SUCCESS(NS_NewURI(getter_AddRefs(appURI), appOrigin),
-                      nsIPrincipal::APP_STATUS_NOT_INSTALLED);
-
-    // The app could contain a cross-origin iframe - make sure that the content
-    // is actually same-origin with the app.
-    MOZ_ASSERT(inIsolatedMozBrowser == false, "Checked this above");
-    nsAutoCString suffix;
-    PrincipalOriginAttributes attrs;
-    NS_ENSURE_TRUE(attrs.PopulateFromOrigin(NS_ConvertUTF16toUTF8(appOrigin), suffix),
-                   nsIPrincipal::APP_STATUS_NOT_INSTALLED);
-    attrs.mAppId = appId;
-    attrs.mInIsolatedMozBrowser = false;
-    nsCOMPtr<nsIPrincipal> appPrin = BasePrincipal::CreateCodebasePrincipal(appURI, attrs);
-    NS_ENSURE_TRUE(appPrin, nsIPrincipal::APP_STATUS_NOT_INSTALLED);
-    return aPrin->Equals(appPrin) ? status
-                                  : nsIPrincipal::APP_STATUS_NOT_INSTALLED;
-}
-
 /*
  * GetChannelResultPrincipal will return the principal that the resource
  * returned by this channel will use.  For example, if the resource is in
diff --git a/caps/tests/mochitest/mochitest.ini b/caps/tests/mochitest/mochitest.ini
index 866553ea26..666a735ae7 100644
--- a/caps/tests/mochitest/mochitest.ini
+++ b/caps/tests/mochitest/mochitest.ini
@@ -4,7 +4,6 @@ support-files =
   file_disableScript.html
   !/js/xpconnect/tests/mochitest/file_empty.html
 
-[test_app_principal_equality.html]
 [test_bug246699.html]
 [test_bug292789.html]
 [test_bug423375.html]
diff --git a/caps/tests/mochitest/test_app_principal_equality.html b/caps/tests/mochitest/test_app_principal_equality.html
deleted file mode 100644
index f59f1f7893..0000000000
--- a/caps/tests/mochitest/test_app_principal_equality.html
+++ /dev/null
@@ -1,88 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=777467
--->
-<head>
-  <meta charset="utf-8">
-  <title>Test app principal's equality</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=777467">Mozilla Bug 777467</a>
-<p id="display"></p>
-<script>
-
-/** Test for app principal's equality **/
-
-SimpleTest.waitForExplicitFinish();
-
-var permissions = new Promise(resolve => {
-  SpecialPowers.pushPermissions(
-    [{ type: "browser", allow: true, context: document },
-     { type: "embed-apps", allow: true, context: document }],
-    resolve);
-});
-
-permissions.then(() => {
-  $('content').innerHTML =
-    '<iframe src="error404"></iframe>\n' +
-    '<iframe mozbrowser src="error404"></iframe>\n' +
-    '<iframe mozapp="http://example.org/manifest.webapp" mozbrowser src="error404"></iframe>';
-
-  var iframes = document.getElementsByTagName("iframe");
-  var promises = []
-  for (var i = 0; i < promises.length; ++i) {
-    promises.push(new Promise(resolve => {
-      iframes[i].addEventListener("load", resolve);
-    }));
-  }
-
-  return Promise.all(promises);
-});
-
-var prefs = new Promise(resolve => {
-  SpecialPowers.pushPrefEnv(
-    { set: [[ "dom.mozBrowserFramesEnabled", true ],
-            [ "dom.ipc.browser_frames.oop_by_default", false ]] },
-    resolve);
-});
-</script>
-<div id="content" style="display: none;">
-</div>
-<pre id="test">
-<script type="application/javascript">
-
-function canAccessDocument(win) {
-  var result = true;
-  try {
-    win.document;
-  } catch(e) {
-    result = false;
-  }
-  return result;
-}
-
-var loaded = new Promise(resolve => addLoadEvent(resolve));
-
-Promise.all([ permissions, prefs, loaded ]).then(runTest);
-
-function runTest() {
-  // Test the witness frame (we can access same-origin frame).
-  is(canAccessDocument(frames[0]), true,
-     "should be able to access the first frame");
-
-  // Test different app/browserElement frames.
-  for (var i=1; i<frames.length; ++i) {
-    is(canAccessDocument(frames[i]), false,
-       "should not be able to access the other frames");
-  }
-
-  SimpleTest.finish();
-}
-
-</script>
-</pre>
-</body>
-</html>
diff --git a/devtools/server/actors/webconsole.js b/devtools/server/actors/webconsole.js
index 106b0e4e04..45414326ef 100644
--- a/devtools/server/actors/webconsole.js
+++ b/devtools/server/actors/webconsole.js
@@ -569,11 +569,9 @@ WebConsoleActor.prototype =
 
     let startedListeners = [];
     let window = !this.parentActor.isRootActor ? this.window : null;
-    let appId = null;
     let messageManager = null;
 
     if (this._parentIsContentActor) {
-      appId = this.parentActor.docShell.appId;
       messageManager = this.parentActor.messageManager;
     }
 
@@ -604,16 +602,16 @@ WebConsoleActor.prototype =
             // Create a StackTraceCollector that's going to be shared both by the
             // NetworkMonitorChild (getting messages about requests from parent) and
             // by the NetworkMonitor that directly watches service workers requests.
-            this.stackTraceCollector = new StackTraceCollector({ window, appId });
+            this.stackTraceCollector = new StackTraceCollector({ window });
             this.stackTraceCollector.init();
 
             let processBoundary = Services.appinfo.processType !=
                                   Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT;
-            if ((appId || messageManager) && processBoundary) {
+            if (messageManager && processBoundary) {
               // Start a network monitor in the parent process to listen to
               // most requests than happen in parent
               this.networkMonitor =
-                new NetworkMonitorChild(appId, this.parentActor.outerWindowID,
+                new NetworkMonitorChild(this.parentActor.outerWindowID,
                                         messageManager, this.conn, this);
               this.networkMonitor.init();
               // Spawn also one in the child to listen to service workers
diff --git a/devtools/shared/layout/utils.js b/devtools/shared/layout/utils.js
index bbe6df4c85..c6b996bebf 100644
--- a/devtools/shared/layout/utils.js
+++ b/devtools/shared/layout/utils.js
@@ -37,12 +37,12 @@ function getTopWindow(win) {
                     .getInterface(Ci.nsIWebNavigation)
                     .QueryInterface(Ci.nsIDocShell);
 
-  if (!docShell.isMozBrowserOrApp) {
+  if (!docShell.isMozBrowser) {
     return win.top;
   }
 
   let topDocShell =
-    docShell.getSameTypeRootTreeItemIgnoreBrowserAndAppBoundaries();
+    docShell.getSameTypeRootTreeItemIgnoreBrowserBoundaries();
 
   return topDocShell
           ? topDocShell.contentViewer.DOMDocument.defaultView
@@ -98,12 +98,12 @@ function getParentWindow(win) {
                  .getInterface(Ci.nsIWebNavigation)
                  .QueryInterface(Ci.nsIDocShell);
 
-  if (!docShell.isMozBrowserOrApp) {
+  if (!docShell.isMozBrowser) {
     return win.parent;
   }
 
   let parentDocShell =
-    docShell.getSameTypeParentIgnoreBrowserAndAppBoundaries();
+    docShell.getSameTypeParentIgnoreBrowserBoundaries();
 
   return parentDocShell
           ? parentDocShell.contentViewer.DOMDocument.defaultView
diff --git a/devtools/shared/webconsole/network-monitor.js b/devtools/shared/webconsole/network-monitor.js
index 8e61f4fc7c..505859c157 100644
--- a/devtools/shared/webconsole/network-monitor.js
+++ b/devtools/shared/webconsole/network-monitor.js
@@ -1551,8 +1551,6 @@ NetworkMonitor.prototype = {
  * data to the WebConsoleActor or to a NetworkEventActor.
  *
  * @constructor
- * @param number appId
- *        The web appId of the child process.
  * @param number outerWindowID
  *        The outerWindowID of the TabActor's main window.
  * @param nsIMessageManager messageManager
@@ -1562,8 +1560,7 @@ NetworkMonitor.prototype = {
  * @param object owner
  *        The WebConsoleActor that is listening for the network requests.
  */
-function NetworkMonitorChild(appId, outerWindowID, messageManager, conn, owner) {
-  this.appId = appId;
+function NetworkMonitorChild(outerWindowID, messageManager, conn, owner) {
   this.outerWindowID = outerWindowID;
   this.conn = conn;
   this.owner = owner;
@@ -1577,7 +1574,6 @@ function NetworkMonitorChild(appId, outerWindowID, messageManager, conn, owner)
 exports.NetworkMonitorChild = NetworkMonitorChild;
 
 NetworkMonitorChild.prototype = {
-  appId: null,
   owner: null,
   _netEvents: null,
   _saveRequestAndResponseBodies: true,
@@ -1623,7 +1619,6 @@ NetworkMonitorChild.prototype = {
     mm.addMessageListener(`${this._msgName}:newEvent`, this._onNewEvent);
     mm.addMessageListener(`${this._msgName}:updateEvent`, this._onUpdateEvent);
     mm.sendAsyncMessage(this._msgName, {
-      appId: this.appId,
       outerWindowID: this.outerWindowID,
       action: "start",
     });
diff --git a/docshell/base/LoadContext.cpp b/docshell/base/LoadContext.cpp
index 4c265e4246..db750ead9c 100644
--- a/docshell/base/LoadContext.cpp
+++ b/docshell/base/LoadContext.cpp
@@ -157,28 +157,6 @@ LoadContext::SetRemoteTabs(bool aUseRemoteTabs)
   return NS_ERROR_UNEXPECTED;
 }
 
-NS_IMETHODIMP
-LoadContext::GetIsInIsolatedMozBrowserElement(bool* aIsInIsolatedMozBrowserElement)
-{
-  MOZ_ASSERT(mIsNotNull);
-
-  NS_ENSURE_ARG_POINTER(aIsInIsolatedMozBrowserElement);
-
-  *aIsInIsolatedMozBrowserElement = mOriginAttributes.mInIsolatedMozBrowser;
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-LoadContext::GetAppId(uint32_t* aAppId)
-{
-  MOZ_ASSERT(mIsNotNull);
-
-  NS_ENSURE_ARG_POINTER(aAppId);
-
-  *aAppId = mOriginAttributes.mAppId;
-  return NS_OK;
-}
-
 NS_IMETHODIMP
 LoadContext::GetOriginAttributes(JS::MutableHandleValue aAttrs)
 {
diff --git a/docshell/base/LoadContext.h b/docshell/base/LoadContext.h
index 90a6a600b8..9714128d8d 100644
--- a/docshell/base/LoadContext.h
+++ b/docshell/base/LoadContext.h
@@ -38,8 +38,6 @@ public:
   NS_DECL_NSILOADCONTEXT
   NS_DECL_NSIINTERFACEREQUESTOR
 
-  // appId/inIsolatedMozBrowser arguments override those in SerializedLoadContext
-  // provided by child process.
   LoadContext(const IPC::SerializedLoadContext& aToCopy,
               dom::Element* aTopFrameElement,
               DocShellOriginAttributes& aAttrs)
@@ -54,8 +52,6 @@ public:
   {
   }
 
-  // appId/inIsolatedMozBrowser arguments override those in SerializedLoadContext
-  // provided by child process.
   LoadContext(const IPC::SerializedLoadContext& aToCopy,
               uint64_t aNestedFrameId,
               DocShellOriginAttributes& aAttrs)
diff --git a/docshell/base/nsDSURIContentListener.cpp b/docshell/base/nsDSURIContentListener.cpp
index 7aa3a5d14d..30213a9833 100644
--- a/docshell/base/nsDSURIContentListener.cpp
+++ b/docshell/base/nsDSURIContentListener.cpp
@@ -334,7 +334,7 @@ nsDSURIContentListener::CheckOneFrameOptionsPolicy(nsIHttpChannel* aHttpChannel,
            curDocShellItem->GetParent(getter_AddRefs(parentDocShellItem))) &&
          parentDocShellItem) {
     nsCOMPtr<nsIDocShell> curDocShell = do_QueryInterface(curDocShellItem);
-    if (curDocShell && curDocShell->GetIsMozBrowserOrApp()) {
+    if (curDocShell && curDocShell->GetIsMozBrowser()) {
       break;
     }
 
@@ -427,6 +427,7 @@ ShouldIgnoreFrameOptions(nsIChannel* aChannel, nsIPrincipal* aPrincipal)
     return false;
   }
 
+#ifdef DEBUG
   // log warning to console that xfo is ignored because of CSP
   nsCOMPtr<nsILoadInfo> loadInfo = aChannel->GetLoadInfo();
   uint64_t innerWindowID = loadInfo ? loadInfo->GetInnerWindowID() : 0;
@@ -440,7 +441,7 @@ ShouldIgnoreFrameOptions(nsIChannel* aChannel, nsIPrincipal* aPrincipal)
                       0,             // no columnnumber
                       nsIScriptError::warningFlag,
                       "CSP", innerWindowID);
-
+#endif
   return true;
 }
 
diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index 7ad4be98da..770eb43119 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -193,7 +193,6 @@
 #include "nsSandboxFlags.h"
 #include "nsXULAppAPI.h"
 #include "nsDOMNavigationTiming.h"
-#include "nsIAppsService.h"
 #include "nsDSURIContentListener.h"
 #include "nsDocShellLoadTypes.h"
 #include "nsDocShellTransferableHooks.h"
@@ -2569,7 +2568,7 @@ nsDocShell::GetFullscreenAllowed(bool* aFullscreenAllowed)
 NS_IMETHODIMP
 nsDocShell::SetFullscreenAllowed(bool aFullscreenAllowed)
 {
-  if (!nsIDocShell::GetIsMozBrowserOrApp()) {
+  if (!nsIDocShell::GetIsMozBrowser()) {
     // Only allow setting of fullscreenAllowed on content/process boundaries.
     // At non-boundaries the fullscreenAllowed attribute is calculated based on
     // whether all enclosing frames have the "mozFullscreenAllowed" attribute
@@ -3401,7 +3400,7 @@ nsDocShell::GetSameTypeParent(nsIDocShellTreeItem** aParent)
   NS_ENSURE_ARG_POINTER(aParent);
   *aParent = nullptr;
 
-  if (nsIDocShell::GetIsMozBrowserOrApp()) {
+  if (nsIDocShell::GetIsMozBrowser()) {
     return NS_OK;
   }
 
@@ -3418,7 +3417,7 @@ nsDocShell::GetSameTypeParent(nsIDocShellTreeItem** aParent)
 }
 
 NS_IMETHODIMP
-nsDocShell::GetSameTypeParentIgnoreBrowserAndAppBoundaries(nsIDocShell** aParent)
+nsDocShell::GetSameTypeParentIgnoreBrowserBoundaries(nsIDocShell** aParent)
 {
   NS_ENSURE_ARG_POINTER(aParent);
   *aParent = nullptr;
@@ -3472,18 +3471,18 @@ nsDocShell::GetSameTypeRootTreeItem(nsIDocShellTreeItem** aRootTreeItem)
 }
 
 NS_IMETHODIMP
-nsDocShell::GetSameTypeRootTreeItemIgnoreBrowserAndAppBoundaries(nsIDocShell ** aRootTreeItem)
+nsDocShell::GetSameTypeRootTreeItemIgnoreBrowserBoundaries(nsIDocShell ** aRootTreeItem)
 {
     NS_ENSURE_ARG_POINTER(aRootTreeItem);
     *aRootTreeItem = static_cast<nsIDocShell *>(this);
 
     nsCOMPtr<nsIDocShell> parent;
-    NS_ENSURE_SUCCESS(GetSameTypeParentIgnoreBrowserAndAppBoundaries(getter_AddRefs(parent)),
+    NS_ENSURE_SUCCESS(GetSameTypeParentIgnoreBrowserBoundaries(getter_AddRefs(parent)),
                       NS_ERROR_FAILURE);
     while (parent) {
       *aRootTreeItem = parent;
       NS_ENSURE_SUCCESS((*aRootTreeItem)->
-        GetSameTypeParentIgnoreBrowserAndAppBoundaries(getter_AddRefs(parent)),
+        GetSameTypeParentIgnoreBrowserBoundaries(getter_AddRefs(parent)),
         NS_ERROR_FAILURE);
     }
     NS_ADDREF(*aRootTreeItem);
@@ -3537,12 +3536,6 @@ nsDocShell::CanAccessItem(nsIDocShellTreeItem* aTargetItem,
     return false;
   }
 
-  if (targetDS->GetIsInIsolatedMozBrowserElement() !=
-        accessingDS->GetIsInIsolatedMozBrowserElement() ||
-      targetDS->GetAppId() != accessingDS->GetAppId()) {
-    return false;
-  }
-
   nsCOMPtr<nsIDocShellTreeItem> accessingRoot;
   aAccessingItem->GetSameTypeRootTreeItem(getter_AddRefs(accessingRoot));
   nsCOMPtr<nsIDocShell> accessingRootDS = do_QueryInterface(accessingRoot);
@@ -3563,7 +3556,7 @@ nsDocShell::CanAccessItem(nsIDocShellTreeItem* aTargetItem,
   if (OriginAttributes::IsFirstPartyEnabled()) {
     if (accessingDS == accessingRootDS &&
         aAccessingItem->ItemType() == nsIDocShellTreeItem::typeContent &&
-        !accessingDS->GetIsMozBrowserOrApp()) {
+        !accessingDS->GetIsMozBrowser()) {
 
       nsCOMPtr<nsIDocument> accessingDoc = aAccessingItem->GetDocument();
 
@@ -3577,7 +3570,7 @@ nsDocShell::CanAccessItem(nsIDocShellTreeItem* aTargetItem,
 
     if (targetDS == targetRootDS &&
         aTargetItem->ItemType() == nsIDocShellTreeItem::typeContent &&
-        !targetDS->GetIsMozBrowserOrApp()) {
+        !targetDS->GetIsMozBrowser()) {
 
       nsCOMPtr<nsIDocument> targetDoc = aAccessingItem->GetDocument();
 
@@ -3774,7 +3767,7 @@ nsDocShell::DoFindItemWithName(const nsAString& aName,
 
     // If we have a same-type parent, respecting browser and app boundaries.
     // NOTE: Could use GetSameTypeParent if the issues described in bug 1310344 are fixed.
-    if (!GetIsMozBrowserOrApp() && parentAsTreeItem->ItemType() == mItemType) {
+    if (!GetIsMozBrowser() && parentAsTreeItem->ItemType() == mItemType) {
       return parentAsTreeItem->FindItemWithName(
         aName,
         static_cast<nsIDocShellTreeItem*>(this),
@@ -5312,16 +5305,6 @@ nsDocShell::LoadErrorPage(nsIURI* aURI, const char16_t* aURL,
   errorPageUrl.AppendLiteral("&f=");
   errorPageUrl.AppendASCII(frameType.get());
 
-  // Append the manifest URL if the error comes from an app.
-  nsString manifestURL;
-  nsresult rv = GetAppManifestURL(manifestURL);
-  if (manifestURL.Length() > 0) {
-    nsCString manifestParam;
-    SAFE_ESCAPE(manifestParam, NS_ConvertUTF16toUTF8(manifestURL), url_Path);
-    errorPageUrl.AppendLiteral("&m=");
-    errorPageUrl.AppendASCII(manifestParam.get());
-  }
-
   nsCOMPtr<nsICaptivePortalService> cps = do_GetService(NS_CAPTIVEPORTAL_CID);
   int32_t cpsState;
   if (cps && NS_SUCCEEDED(cps->GetState(&cpsState)) &&
@@ -5335,7 +5318,7 @@ nsDocShell::LoadErrorPage(nsIURI* aURI, const char16_t* aURL,
   errorPageUrl.AppendASCII(escapedDescription.get());
 
   nsCOMPtr<nsIURI> errorPageURI;
-  rv = NS_NewURI(getter_AddRefs(errorPageURI), errorPageUrl);
+  nsresult rv = NS_NewURI(getter_AddRefs(errorPageURI), errorPageUrl);
   NS_ENSURE_SUCCESS(rv, rv);
 
   return InternalLoad(errorPageURI, nullptr, false, false,
@@ -6222,9 +6205,7 @@ nsDocShell::SetIsActive(bool aIsActive)
     mScriptGlobal->SetIsBackground(!aIsActive);
     if (nsCOMPtr<nsIDocument> doc = mScriptGlobal->GetExtantDoc()) {
       // Update orientation when the top-level browsing context becomes active.
-      // We make an exception for apps because they currently rely on
-      // orientation locks persisting across browsing contexts.
-      if (aIsActive && !GetIsApp()) {
+      if (aIsActive) {
         nsCOMPtr<nsIDocShellTreeItem> parent;
         GetSameTypeParent(getter_AddRefs(parent));
         if (!parent) {
@@ -6261,7 +6242,7 @@ nsDocShell::SetIsActive(bool aIsActive)
       continue;
     }
 
-    if (!docshell->GetIsMozBrowserOrApp()) {
+    if (!docshell->GetIsMozBrowser()) {
       docshell->SetIsActive(aIsActive);
     }
   }
@@ -10636,9 +10617,7 @@ nsDocShell::InternalLoad(nsIURI* aURI,
   // lock the orientation of the document to the document's default
   // orientation. We don't explicitly check for a top-level browsing context
   // here because orientation is only set on top-level browsing contexts.
-  // We make an exception for apps because they currently rely on
-  // orientation locks persisting across browsing contexts.
-  if (OrientationLock() != eScreenOrientation_None && !GetIsApp()) {
+  if (OrientationLock() != eScreenOrientation_None) {
 #ifdef DEBUG
     nsCOMPtr<nsIDocShellTreeItem> parent;
     GetSameTypeParent(getter_AddRefs(parent));
@@ -11023,7 +11002,7 @@ nsDocShell::DoURILoad(nsIURI* aURI,
   NeckoOriginAttributes neckoAttrs;
   bool isTopLevelDoc = aContentPolicyType == nsIContentPolicy::TYPE_DOCUMENT &&
                        mItemType == typeContent &&
-                       !GetIsMozBrowserOrApp();
+                       !GetIsMozBrowser();
   neckoAttrs.InheritFromDocShellToNecko(GetOriginAttributes(), isTopLevelDoc, aURI);
   rv = loadInfo->SetOriginAttributes(neckoAttrs);
   if (NS_WARN_IF(NS_FAILED(rv))) {
@@ -14480,16 +14459,9 @@ nsDocShell::GetFrameType(uint32_t* aFrameType)
 }
 
 /* [infallible] */ NS_IMETHODIMP
-nsDocShell::GetIsApp(bool* aIsApp)
+nsDocShell::GetIsMozBrowser(bool* aIsMozBrowser)
 {
-  *aIsApp = (mFrameType == FRAME_TYPE_APP);
-  return NS_OK;
-}
-
-/* [infallible] */ NS_IMETHODIMP
-nsDocShell::GetIsMozBrowserOrApp(bool* aIsMozBrowserOrApp)
-{
-  *aIsMozBrowserOrApp = (mFrameType != FRAME_TYPE_REGULAR);
+  *aIsMozBrowser = (mFrameType == FRAME_TYPE_BROWSER);
   return NS_OK;
 }
 
@@ -14512,30 +14484,9 @@ nsDocShell::GetInheritedFrameType()
 }
 
 /* [infallible] */ NS_IMETHODIMP
-nsDocShell::GetIsIsolatedMozBrowserElement(bool* aIsIsolatedMozBrowserElement)
+nsDocShell::GetIsInMozBrowser(bool* aIsInMozBrowser)
 {
-  bool result = mFrameType == FRAME_TYPE_BROWSER &&
-                mOriginAttributes.mInIsolatedMozBrowser;
-  *aIsIsolatedMozBrowserElement = result;
-  return NS_OK;
-}
-
-/* [infallible] */ NS_IMETHODIMP
-nsDocShell::GetIsInIsolatedMozBrowserElement(bool* aIsInIsolatedMozBrowserElement)
-{
-  MOZ_ASSERT(!mOriginAttributes.mInIsolatedMozBrowser ||
-             (GetInheritedFrameType() == FRAME_TYPE_BROWSER),
-             "Isolated mozbrowser should only be true inside browser frames");
-  bool result = (GetInheritedFrameType() == FRAME_TYPE_BROWSER) &&
-                mOriginAttributes.mInIsolatedMozBrowser;
-  *aIsInIsolatedMozBrowserElement = result;
-  return NS_OK;
-}
-
-/* [infallible] */ NS_IMETHODIMP
-nsDocShell::GetIsInMozBrowserOrApp(bool* aIsInMozBrowserOrApp)
-{
-  *aIsInMozBrowserOrApp = (GetInheritedFrameType() != FRAME_TYPE_REGULAR);
+  *aIsInMozBrowser = (GetInheritedFrameType() == FRAME_TYPE_BROWSER);
   return NS_OK;
 }
 
@@ -14553,25 +14504,6 @@ nsDocShell::GetIsTopLevelContentDocShell(bool* aIsTopLevelContentDocShell)
   return NS_OK;
 }
 
-/* [infallible] */ NS_IMETHODIMP
-nsDocShell::GetAppId(uint32_t* aAppId)
-{
-  if (mOriginAttributes.mAppId != nsIScriptSecurityManager::UNKNOWN_APP_ID) {
-    *aAppId = mOriginAttributes.mAppId;
-    return NS_OK;
-  }
-
-  nsCOMPtr<nsIDocShell> parent;
-  GetSameTypeParentIgnoreBrowserAndAppBoundaries(getter_AddRefs(parent));
-
-  if (!parent) {
-    *aAppId = nsIScriptSecurityManager::NO_APP_ID;
-    return NS_OK;
-  }
-
-  return parent->GetAppId(aAppId);
-}
-
 // Implements nsILoadContext.originAttributes
 NS_IMETHODIMP
 nsDocShell::GetOriginAttributes(JS::MutableHandle<JS::Value> aVal)
@@ -14680,23 +14612,6 @@ nsDocShell::SetOriginAttributes(JS::Handle<JS::Value> aOriginAttributes,
   return SetOriginAttributes(attrs);
 }
 
-NS_IMETHODIMP
-nsDocShell::GetAppManifestURL(nsAString& aAppManifestURL)
-{
-  uint32_t appId = nsIDocShell::GetAppId();
-  if (appId != nsIScriptSecurityManager::NO_APP_ID &&
-      appId != nsIScriptSecurityManager::UNKNOWN_APP_ID) {
-    nsCOMPtr<nsIAppsService> appsService =
-      do_GetService(APPS_SERVICE_CONTRACTID);
-    NS_ASSERTION(appsService, "No AppsService available");
-    appsService->GetManifestURLByLocalId(appId, aAppManifestURL);
-  } else {
-    aAppManifestURL.SetLength(0);
-  }
-
-  return NS_OK;
-}
-
 NS_IMETHODIMP
 nsDocShell::GetAsyncPanZoomEnabled(bool* aOut)
 {
diff --git a/docshell/base/nsDocShell.h b/docshell/base/nsDocShell.h
index 396996ea74..2bb71911b9 100644
--- a/docshell/base/nsDocShell.h
+++ b/docshell/base/nsDocShell.h
@@ -789,8 +789,6 @@ protected:
   static const nsCString FrameTypeToString(uint32_t aFrameType)
   {
     switch (aFrameType) {
-      case FRAME_TYPE_APP:
-        return NS_LITERAL_CSTRING("app");
       case FRAME_TYPE_BROWSER:
         return NS_LITERAL_CSTRING("browser");
       case FRAME_TYPE_REGULAR:
diff --git a/docshell/base/nsIDocShell.idl b/docshell/base/nsIDocShell.idl
index d2812bd9c9..516d3981c4 100644
--- a/docshell/base/nsIDocShell.idl
+++ b/docshell/base/nsIDocShell.idl
@@ -826,109 +826,50 @@ interface nsIDocShell : nsIDocShellTreeItem
    */
   [noscript] void notifyScrollObservers();
 
-  /**
-   * Returns true iff the docshell corresponds to an <iframe mozapp>.
-   */
-  [infallible] readonly attribute boolean isApp;
-
   /**
    * The type of iframe that this docshell lives.
    */
   const unsigned long FRAME_TYPE_REGULAR = 0;
   const unsigned long FRAME_TYPE_BROWSER = 1;
-  const unsigned long FRAME_TYPE_APP     = 2;
 
   [infallible] attribute unsigned long frameType;
 
   /**
-   * Returns true if this docshell corresponds to an <iframe mozbrowser> or
-   * <iframe mozapp>.  <xul:browser> returns false here.
+   * Returns true if this docshell corresponds to an <iframe mozbrowser>.
+   * <xul:browser> returns false here.
    */
-  [infallible] readonly attribute boolean isMozBrowserOrApp;
+  [infallible] readonly attribute boolean isMozBrowser;
 
   /**
-   * Returns true if this docshell corresponds to an isolated <iframe
-   * mozbrowser>.
-   *
-   * <iframe mozbrowser mozapp> and <xul:browser> are not considered to be
-   * mozbrowser elements.  <iframe mozbrowser noisolation> does not count as
-   * isolated since isolation is disabled.  Isolation can only be disabled if
-   * the containing document is chrome.
-   */
-  [infallible] readonly attribute boolean isIsolatedMozBrowserElement;
-
-  /**
-   * Returns true if this docshell corresponds to an isolated <iframe
-   * mozbrowser> or if the docshell is contained in an isolated <iframe
-   * mozbrowser>.
-   *
-   * <iframe mozbrowser mozapp> and <xul:browser> are not considered to be
-   * mozbrowser elements.  <iframe mozbrowser noisolation> does not count as
-   * isolated since isolation is disabled.  Isolation can only be disabled if
-   * the containing document is chrome.
-   *
-   * Our notion here of "contained in" means: Walk up the docshell hierarchy in
-   * this process until we hit an <iframe mozapp> or <iframe mozbrowser> (or
-   * until the hierarchy ends).  Return true iff the docshell we stopped on has
-   * isIsolatedMozBrowserElement == true.
-   */
-  [infallible] readonly attribute boolean isInIsolatedMozBrowserElement;
-
-  /**
-   * Returns true if this docshell corresponds to an <iframe mozbrowser> or
-   * <iframe mozapp>, or if this docshell is contained in an <iframe mozbrowser>
-   * or <iframe mozapp>.  <xul:browser> returns false here.
+   * Returns true if this docshell corresponds to an <iframe mozbrowser>, or
+   * if this docshell is contained in an <iframe mozbrowser>. <xul:browser>
+   * returns false here.
    *
    * To compute this value, we walk up the docshell hierarchy.  If we encounter
-   * a docshell with isMozBrowserOrApp before we hit the end of the hierarchy,
+   * a docshell with isMozBrowser before we hit the end of the hierarchy,
    * we return true.  Otherwise, we return false.
    */
-  [infallible] readonly attribute boolean isInMozBrowserOrApp;
+  [infallible] readonly attribute boolean isInMozBrowser;
 
   /**
    * Returns true if this docshell is the top level content docshell.
    */
   [infallible] readonly attribute boolean isTopLevelContentDocShell;
 
-  /**
-   * Returns the id of the app associated with this docshell.  If this docshell
-   * is an <iframe mozbrowser> inside an <iframe mozapp>, we return the app's
-   * appId.
-   *
-   * We compute this value by walking up the docshell hierarchy until we find a
-   * docshell on which origin attributes was set. (ignoring those docshells
-   * where x == UNKNOWN_APP_ID).  We return the app id x.
-   *
-   * If we don't find a docshell with an associated app id in our hierarchy, we
-   * return NO_APP_ID.  We never return UNKNOWN_APP_ID.
-   *
-   * Notice that a docshell may have an associated app even if it returns true
-   * for isBrowserElement!
-   */
-  [infallible] readonly attribute unsigned long appId;
-
-  /**
-   * Return the manifest URL of the app associated with this docshell.
-   *
-   * If there is no associated app in our hierarchy, we return empty string.
-   */
-  readonly attribute DOMString appManifestURL;
-
   /**
    * Like nsIDocShellTreeItem::GetSameTypeParent, except this ignores <iframe
-   * mozbrowser> and <iframe mozapp> boundaries.
+   * mozbrowser> boundaries.
    */
-  nsIDocShell getSameTypeParentIgnoreBrowserAndAppBoundaries();
+  nsIDocShell getSameTypeParentIgnoreBrowserBoundaries();
 
   /**
    * Like nsIDocShellTreeItem::GetSameTypeRootTreeItem, except this ignores
-   * <iframe mozbrowser> and <iframe mozapp> boundaries.
+   * <iframe mozbrowser> boundaries.
    */
-  nsIDocShell getSameTypeRootTreeItemIgnoreBrowserAndAppBoundaries();
+  nsIDocShell getSameTypeRootTreeItemIgnoreBrowserBoundaries();
 
   /**
-   * True iff asynchronous panning and zooming is enabled for this
-   * docshell.
+   * True if asynchronous panning and zooming is enabled for this docshell.
    */
   readonly attribute bool asyncPanZoomEnabled;
 
diff --git a/docshell/base/nsIDocShellTreeItem.idl b/docshell/base/nsIDocShellTreeItem.idl
index 431b16c797..e2a3168f32 100644
--- a/docshell/base/nsIDocShellTreeItem.idl
+++ b/docshell/base/nsIDocShellTreeItem.idl
@@ -57,10 +57,9 @@ interface nsIDocShellTreeItem : nsISupports
 
 	/*
 	This getter returns the same thing parent does however if the parent
-	is of a different itemType, or if the parent is an <iframe mozbrowser>
-	or <iframe mozapp>, it will instead return nullptr.  This call is a
-	convience function for those wishing to not cross the boundaries at
-	which item types change.
+	is of a different itemType, or if the parent is an <iframe mozbrowser>.
+	It will instead return nullptr.  This call is a convience function for
+	Ithose wishing to not cross the boundaries at which item types change.
 	*/
 	readonly attribute nsIDocShellTreeItem sameTypeParent;
 
diff --git a/docshell/base/nsILoadContext.idl b/docshell/base/nsILoadContext.idl
index b318c1a5e8..3894a12e34 100644
--- a/docshell/base/nsILoadContext.idl
+++ b/docshell/base/nsILoadContext.idl
@@ -104,21 +104,6 @@ interface nsILoadContext : nsISupports
    */
   [noscript] void SetRemoteTabs(in boolean aUseRemoteTabs);
 
-  /**
-   * Returns true iff the load is occurring inside an isolated mozbrowser
-   * element. <iframe mozbrowser mozapp> and <xul:browser> are not considered to
-   * be mozbrowser elements.  <iframe mozbrowser noisolation> does not count as
-   * isolated since isolation is disabled.  Isolation can only be disabled if
-   * the containing document is chrome.
-   */
-  readonly attribute boolean isInIsolatedMozBrowserElement;
-
-  /**
-   * Returns the app id of the app the load is occurring is in. Returns
-   * nsIScriptSecurityManager::NO_APP_ID if the load is not part of an app.
-   */
-  readonly attribute unsigned long appId;
-
   /**
    * A dictionary of the non-default origin attributes associated with this
    * nsILoadContext.
diff --git a/dom/apps/AppsService.js b/dom/apps/AppsService.js
deleted file mode 100644
index e0a7ea041c..0000000000
--- a/dom/apps/AppsService.js
+++ /dev/null
@@ -1,114 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-"use strict"
-
-function debug(s) {
-  //dump("-*- AppsService.js: " + s + "\n");
-}
-
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const Cu = Components.utils;
-const Cr = Components.results;
-
-Cu.import("resource://gre/modules/XPCOMUtils.jsm");
-Cu.import("resource://gre/modules/Services.jsm");
-Cu.import("resource://gre/modules/Promise.jsm");
-
-const APPS_SERVICE_CID = Components.ID("{05072afa-92fe-45bf-ae22-39b69c117058}");
-
-function AppsService()
-{
-  debug("AppsService Constructor");
-  this.inParent = Cc["@mozilla.org/xre/app-info;1"].getService(Ci.nsIXULRuntime)
-                    .processType == Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT;
-  debug("inParent: " + this.inParent);
-  if (!this.inParent) {
-    Cu.import("resource://gre/modules/AppsServiceChild.jsm");
-  }
-}
-
-AppsService.prototype = {
-
-  isInvalidId: function(localId) {
-    return (localId == Ci.nsIScriptSecurityManager.NO_APP_ID ||
-            localId == Ci.nsIScriptSecurityManager.UNKNOWN_APP_ID);
-  },
-
-  getAppByManifestURL: function getAppByManifestURL(aManifestURL) {
-    debug("GetAppByManifestURL( " + aManifestURL + " )");
-    throw Cr.NS_ERROR_NOT_IMPLEMENTED;
-  },
-
-  getManifestFor: function getManifestFor(aManifestURL) {
-    debug("getManifestFor(" + aManifestURL + ")");
-    if (this.inParent) {
-      throw Cr.NS_ERROR_NOT_IMPLEMENTED;
-    } else {
-      return Promise.reject(
-        new Error("Calling getManifestFor() from child is not supported"));
-    }
-  },
-
-  getAppLocalIdByManifestURL: function getAppLocalIdByManifestURL(aManifestURL) {
-    debug("getAppLocalIdByManifestURL( " + aManifestURL + " )");
-    throw Cr.NS_ERROR_NOT_IMPLEMENTED;
-  },
-
-  getAppLocalIdByStoreId: function getAppLocalIdByStoreId(aStoreId) {
-    debug("getAppLocalIdByStoreId( " + aStoreId + " )");
-    throw Cr.NS_ERROR_NOT_IMPLEMENTED;
-  },
-
-  getAppByLocalId: function getAppByLocalId(aLocalId) {
-    debug("getAppByLocalId( " + aLocalId + " )");
-    if (this.isInvalidId(aLocalId)) {
-      return null;
-    }
-    throw Cr.NS_ERROR_NOT_IMPLEMENTED;
-  },
-
-  getManifestURLByLocalId: function getManifestURLByLocalId(aLocalId) {
-    debug("getManifestURLByLocalId( " + aLocalId + " )");
-    if (this.isInvalidId(aLocalId)) {
-      return null;
-    }
-    throw Cr.NS_ERROR_NOT_IMPLEMENTED;
-  },
-
-  getCoreAppsBasePath: function getCoreAppsBasePath() {
-    debug("getCoreAppsBasePath()");
-    throw Cr.NS_ERROR_NOT_IMPLEMENTED;
-  },
-
-  getWebAppsBasePath: function getWebAppsBasePath() {
-    debug("getWebAppsBasePath()");
-    throw Cr.NS_ERROR_NOT_IMPLEMENTED;
-  },
-
-  areAnyAppsInstalled: function() {
-    throw Cr.NS_ERROR_NOT_IMPLEMENTED;
-  },
-
-  getAppInfo: function getAppInfo(aAppId) {
-    debug("getAppInfo()");
-    throw Cr.NS_ERROR_NOT_IMPLEMENTED;
-  },
-
-  getScopeByLocalId: function(aLocalId) {
-    debug("getScopeByLocalId( " + aLocalId + " )");
-    if (this.isInvalidId(aLocalId)) {
-      return null;
-    }
-    // TODO : implement properly!
-    // We just return null for now to not break PushService.jsm
-    return null;
-  },
-
-  classID : APPS_SERVICE_CID,
-  QueryInterface : XPCOMUtils.generateQI([Ci.nsIAppsService])
-}
-
-this.NSGetFactory = XPCOMUtils.generateNSGetFactory([AppsService])
diff --git a/dom/apps/AppsService.manifest b/dom/apps/AppsService.manifest
deleted file mode 100644
index 2ed92d4e8a..0000000000
--- a/dom/apps/AppsService.manifest
+++ /dev/null
@@ -1,2 +0,0 @@
-component {05072afa-92fe-45bf-ae22-39b69c117058} AppsService.js
-contract @mozilla.org/AppsService;1 {05072afa-92fe-45bf-ae22-39b69c117058}
diff --git a/dom/apps/AppsServiceChild.jsm b/dom/apps/AppsServiceChild.jsm
deleted file mode 100644
index 4aca938af4..0000000000
--- a/dom/apps/AppsServiceChild.jsm
+++ /dev/null
@@ -1,408 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-"use strict";
-
-const Cu = Components.utils;
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-
-// This module exposes a subset of the functionalities of the parent DOM
-// Registry to content processes, to be used from the AppsService component.
-
-this.EXPORTED_SYMBOLS = ["DOMApplicationRegistry", "WrappedManifestCache"];
-
-Cu.import("resource://gre/modules/AppsUtils.jsm");
-Cu.import("resource://gre/modules/Services.jsm");
-
-function debug(s) {
-  //dump("-*- AppsServiceChild.jsm: " + s + "\n");
-}
-
-const APPS_IPC_MSG_NAMES = [
-  "Webapps:AddApp",
-  "Webapps:RemoveApp",
-  "Webapps:UpdateApp",
-  "Webapps:CheckForUpdate:Return:KO",
-  "Webapps:FireEvent",
-  "Webapps:UpdateState"
-];
-
-// A simple cache for the wrapped manifests.
-this.WrappedManifestCache = {
-  _cache: { },
-
-  // Gets an entry from the cache, and populates the cache if needed.
-  get: function mcache_get(aManifestURL, aManifest, aWindow, aInnerWindowID) {
-    if (!aManifest) {
-      return;
-    }
-
-    if (!(aManifestURL in this._cache)) {
-      this._cache[aManifestURL] = { };
-    }
-
-    let winObjs = this._cache[aManifestURL];
-    if (!(aInnerWindowID in winObjs)) {
-      winObjs[aInnerWindowID] = Cu.cloneInto(aManifest, aWindow);
-    }
-
-    return winObjs[aInnerWindowID];
-  },
-
-  // Invalidates an entry in the cache.
-  evict: function mcache_evict(aManifestURL, aInnerWindowID) {
-    debug("Evicting manifest " + aManifestURL + " window ID " +
-          aInnerWindowID);
-    if (aManifestURL in this._cache) {
-      let winObjs = this._cache[aManifestURL];
-      if (aInnerWindowID in winObjs) {
-        delete winObjs[aInnerWindowID];
-      }
-
-      if (Object.keys(winObjs).length == 0) {
-        delete this._cache[aManifestURL];
-      }
-    }
-  },
-
-  observe: function(aSubject, aTopic, aData) {
-    // Clear the cache on memory pressure.
-    this._cache = { };
-    Cu.forceGC();
-  },
-
-  init: function() {
-    Services.obs.addObserver(this, "memory-pressure", false);
-  }
-};
-
-this.WrappedManifestCache.init();
-
-
-// DOMApplicationRegistry keeps a cache containing a list of apps in the device.
-// This information is updated with the data received from the main process and
-// it is queried by the DOM objects to set their state.
-// This module handle all the messages broadcasted from the parent process,
-// including DOM events, which are dispatched to the corresponding DOM objects.
-
-this.DOMApplicationRegistry = {
-  // DOMApps will hold a list of arrays of weak references to
-  // mozIDOMApplication objects indexed by manifest URL.
-  DOMApps: {},
-
-  ready: false,
-  webapps: null,
-
-  init: function init() {
-    this.cpmm = Cc["@mozilla.org/childprocessmessagemanager;1"]
-                  .getService(Ci.nsISyncMessageSender);
-
-    APPS_IPC_MSG_NAMES.forEach((function(aMsgName) {
-      this.cpmm.addMessageListener(aMsgName, this);
-    }).bind(this));
-
-    this.webapps = { };
-    // We need a fast mapping from localId -> app, so we add an index.
-    // We also add the manifest to the app object.
-    this.localIdIndex = { };
-    for (let id in this.webapps) {
-      let app = this.webapps[id];
-      this.localIdIndex[app.localId] = app;
-      app.manifest = list.manifests[id];
-    }
-
-    Services.obs.addObserver(this, "xpcom-shutdown", false);
-  },
-
-  observe: function(aSubject, aTopic, aData) {
-    // cpmm.addMessageListener causes the DOMApplicationRegistry object to
-    // live forever if we don't clean up properly.
-    this.webapps = null;
-    this.DOMApps = null;
-
-    APPS_IPC_MSG_NAMES.forEach((aMsgName) => {
-      this.cpmm.removeMessageListener(aMsgName, this);
-    });
-  },
-
-  receiveMessage: function receiveMessage(aMessage) {
-    debug("Received " + aMessage.name + " message.");
-    let msg = aMessage.data;
-    switch (aMessage.name) {
-      case "Webapps:AddApp":
-        this.webapps[msg.id] = msg.app;
-        this.localIdIndex[msg.app.localId] = msg.app;
-        if (msg.manifest) {
-          this.webapps[msg.id].manifest = msg.manifest;
-        }
-        break;
-      case "Webapps:RemoveApp":
-        delete this.DOMApps[this.webapps[msg.id].manifestURL];
-        delete this.localIdIndex[this.webapps[msg.id].localId];
-        delete this.webapps[msg.id];
-        break;
-      case "Webapps:UpdateApp":
-        let app = this.webapps[msg.oldId];
-        if (!app) {
-          return;
-        }
-
-        if (msg.app) {
-          for (let prop in msg.app) {
-            app[prop] = msg.app[prop];
-          }
-        }
-
-        this.webapps[msg.newId] = app;
-        this.localIdIndex[app.localId] = app;
-        delete this.webapps[msg.oldId];
-
-        let apps = this.DOMApps[msg.app.manifestURL];
-        if (!apps) {
-          return;
-        }
-        for (let i = 0; i < apps.length; i++) {
-          let domApp = apps[i].get();
-          if (!domApp || domApp._window === null) {
-            apps.splice(i, 1);
-            continue;
-          }
-          domApp._proxy = new Proxy(domApp, {
-            get: function(target, prop) {
-              if (!DOMApplicationRegistry.webapps[msg.newId]) {
-                return;
-              }
-              return DOMApplicationRegistry.webapps[msg.newId][prop];
-            },
-            set: function(target, prop, val) {
-              if (!DOMApplicationRegistry.webapps[msg.newId]) {
-                return;
-              }
-              DOMApplicationRegistry.webapps[msg.newId][prop] = val;
-              return;
-            },
-          });
-        }
-        break;
-      case "Webapps:FireEvent":
-        this._fireEvent(aMessage);
-        break;
-      case "Webapps:UpdateState":
-        this._updateState(msg);
-        break;
-      case "Webapps:CheckForUpdate:Return:KO":
-        let DOMApps = this.DOMApps[msg.manifestURL];
-        if (!DOMApps || !msg.requestID) {
-          return;
-        }
-        DOMApps.forEach((DOMApp) => {
-          let domApp = DOMApp.get();
-          if (domApp && msg.requestID) {
-            domApp._fireRequestResult(aMessage, true /* aIsError */);
-          }
-        });
-        break;
-    }
-  },
-
-  /**
-   * mozIDOMApplication management
-   */
-
-  // Every time a DOM app is created, we save a weak reference to it that will
-  // be used to dispatch events and fire request results.
-  addDOMApp: function(aApp, aManifestURL, aId) {
-    let weakRef = Cu.getWeakReference(aApp);
-
-    if (!this.DOMApps[aManifestURL]) {
-      this.DOMApps[aManifestURL] = [];
-    }
-
-    let apps = this.DOMApps[aManifestURL];
-
-    // Get rid of dead weak references.
-    for (let i = 0; i < apps.length; i++) {
-      let app = apps[i].get();
-      if (!app || app._window === null) {
-        apps.splice(i, 1);
-      }
-    }
-
-    apps.push(weakRef);
-
-    // Each DOM app contains a proxy object used to build their state. We
-    // return the handler for this proxy object with traps to get and set
-    // app properties kept in the DOMApplicationRegistry app cache.
-    return {
-      get: function(target, prop) {
-        if (!DOMApplicationRegistry.webapps[aId]) {
-          return;
-        }
-
-        if (prop in DOMApplicationRegistry.webapps[aId]) {
-          return DOMApplicationRegistry.webapps[aId][prop];
-        }
-        return null;
-      },
-      set: function(target, prop, val) {
-        if (!DOMApplicationRegistry.webapps[aId]) {
-          return;
-        }
-        DOMApplicationRegistry.webapps[aId][prop] = val;
-        return;
-      },
-    };
-  },
-
-  _fireEvent: function(aMessage) {
-    let msg = aMessage.data;
-    debug("_fireEvent " + JSON.stringify(msg));
-    if (!this.DOMApps || !msg.manifestURL || !msg.eventType) {
-      return;
-    }
-
-    let DOMApps = this.DOMApps[msg.manifestURL];
-    if (!DOMApps) {
-      return;
-    }
-
-    // The parent might ask childs to trigger more than one event in one
-    // shot, so in order to avoid needless IPC we allow an array for the
-    // 'eventType' IPC message field.
-    if (!Array.isArray(msg.eventType)) {
-      msg.eventType = [msg.eventType];
-    }
-
-    DOMApps.forEach((DOMApp) => {
-      let domApp = DOMApp.get();
-      if (!domApp) {
-        return;
-      }
-      msg.eventType.forEach((aEventType) => {
-        if ('on' + aEventType in domApp) {
-          domApp._fireEvent(aEventType);
-        }
-      });
-
-      if (msg.requestID) {
-        aMessage.data.result = msg.manifestURL;
-        domApp._fireRequestResult(aMessage);
-      }
-    });
-  },
-
-  _updateState: function(aMessage) {
-    if (!this.DOMApps || !aMessage.id) {
-      return;
-    }
-
-    let app = this.webapps[aMessage.id];
-    if (!app) {
-      return;
-    }
-
-    if (aMessage.app) {
-      for (let prop in aMessage.app) {
-        app[prop] = aMessage.app[prop];
-      }
-    }
-
-    if ("error" in aMessage) {
-      app.downloadError = aMessage.error;
-    }
-
-    if (aMessage.manifest) {
-      app.manifest = aMessage.manifest;
-      // Evict the wrapped manifest cache for all the affected DOM objects.
-      let DOMApps = this.DOMApps[app.manifestURL];
-      if (!DOMApps) {
-        return;
-      }
-      DOMApps.forEach((DOMApp) => {
-        let domApp = DOMApp.get();
-        if (!domApp) {
-          return;
-        }
-        WrappedManifestCache.evict(app.manifestURL, domApp.innerWindowID);
-      });
-    }
-  },
-
-  getAll: function(aCallback) {
-    debug("getAll()\n");
-    if (!aCallback || typeof aCallback !== "function") {
-      return;
-    }
-
-    let res = [];
-    for (let id in this.webapps) {
-      res.push(this.webapps[id]);
-    }
-    aCallback(res);
-  },
-
-  getAdditionalLanguages: function(aManifestURL) {
-    for (let id in this.webapps) {
-      if (this.webapps[id].manifestURL == aManifestURL) {
-        return this.webapps[id].additionalLanguages || {};
-      }
-    }
-    return {};
-  },
-
-  /**
-   * nsIAppsService API
-   */
-  getAppByManifestURL: function getAppByManifestURL(aManifestURL) {
-    debug("getAppByManifestURL " + aManifestURL);
-    return AppsUtils.getAppByManifestURL(this.webapps, aManifestURL);
-  },
-
-  getAppLocalIdByManifestURL: function getAppLocalIdByManifestURL(aManifestURL) {
-    debug("getAppLocalIdByManifestURL " + aManifestURL);
-    return AppsUtils.getAppLocalIdByManifestURL(this.webapps, aManifestURL);
-  },
-
-  getAppLocalIdByStoreId: function(aStoreId) {
-    debug("getAppLocalIdByStoreId:" + aStoreId);
-    return AppsUtils.getAppLocalIdByStoreId(this.webapps, aStoreId);
-  },
-
-  getAppByLocalId: function getAppByLocalId(aLocalId) {
-    debug("getAppByLocalId " + aLocalId + " - ready: " + this.ready);
-    let app = this.localIdIndex[aLocalId];
-    if (!app) {
-      debug("Ouch, No app!");
-      return null;
-    }
-
-    return new mozIApplication(app);
-  },
-
-  getManifestURLByLocalId: function getManifestURLByLocalId(aLocalId) {
-    debug("getManifestURLByLocalId " + aLocalId);
-    return AppsUtils.getManifestURLByLocalId(this.webapps, aLocalId);
-  },
-
-  getCoreAppsBasePath: function getCoreAppsBasePath() {
-    debug("getCoreAppsBasePath() not yet supported on child!");
-    return null;
-  },
-
-  getWebAppsBasePath: function getWebAppsBasePath() {
-    debug("getWebAppsBasePath() not yet supported on child!");
-    return null;
-  },
-
-  areAnyAppsInstalled: function() {
-    return AppsUtils.areAnyAppsInstalled(this.webapps);
-  },
-
-  getAppInfo: function getAppInfo(aAppId) {
-    return AppsUtils.getAppInfo(this.webapps, aAppId);
-  }
-}
-
-DOMApplicationRegistry.init();
diff --git a/dom/apps/AppsUtils.jsm b/dom/apps/AppsUtils.jsm
index d24dee8c23..5a70b352f1 100644
--- a/dom/apps/AppsUtils.jsm
+++ b/dom/apps/AppsUtils.jsm
@@ -19,14 +19,10 @@ XPCOMUtils.defineLazyModuleGetter(this, "FileUtils",
 XPCOMUtils.defineLazyModuleGetter(this, "NetUtil",
   "resource://gre/modules/NetUtil.jsm");
 
-XPCOMUtils.defineLazyServiceGetter(this, "appsService",
-                                   "@mozilla.org/AppsService;1",
-                                   "nsIAppsService");
-
-// Shared code for AppsServiceChild.jsm, Webapps.jsm and Webapps.js
+// Shared code for Webapps.jsm and Webapps.js
 
 this.EXPORTED_SYMBOLS =
-  ["AppsUtils", "ManifestHelper", "isAbsoluteURI", "mozIApplication"];
+  ["AppsUtils", "ManifestHelper", "isAbsoluteURI"];
 
 function debug(s) {
   //dump("-*- AppsUtils.jsm: " + s + "\n");
@@ -39,46 +35,6 @@ this.isAbsoluteURI = function(aURI) {
          Services.io.newURI(aURI, null, bar).prePath != bar.prePath;
 }
 
-this.mozIApplication = function(aApp) {
-  _setAppProperties(this, aApp);
-}
-
-mozIApplication.prototype = {
-  hasPermission: function(aPermission) {
-    // This helper checks an URI inside |aApp|'s origin and part of |aApp| has a
-    // specific permission. It is not checking if browsers inside |aApp| have such
-    // permission.
-    let perm = Services.perms.testExactPermissionFromPrincipal(this.principal,
-                                                               aPermission);
-    return (perm === Ci.nsIPermissionManager.ALLOW_ACTION);
-  },
-
-  get principal() {
-    if (this._principal) {
-      return this._principal;
-    }
-
-    this._principal = null;
-
-    try {
-      this._principal = Services.scriptSecurityManager.createCodebasePrincipal(
-        Services.io.newURI(this.origin, null, null),
-        {appId: this.localId});
-    } catch(e) {
-      dump("Could not create app principal " + e + "\n");
-    }
-
-    return this._principal;
-  },
-
-  QueryInterface: function(aIID) {
-    if (aIID.equals(Ci.mozIApplication) ||
-        aIID.equals(Ci.nsISupports))
-      return this;
-    throw Cr.NS_ERROR_NO_INTERFACE;
-  }
-}
-
 function _setAppProperties(aObj, aApp) {
   aObj.name = aApp.name;
   aObj.csp = aApp.csp;
@@ -217,21 +173,6 @@ this.AppsUtils = {
     return aPagePath.substr(pathPos, pathLen);
   },
 
-  getAppByManifestURL: function getAppByManifestURL(aApps, aManifestURL) {
-    debug("getAppByManifestURL " + aManifestURL);
-    // This could be O(1) if |webapps| was a dictionary indexed on manifestURL
-    // which should be the unique app identifier.
-    // It's currently O(n).
-    for (let id in aApps) {
-      let app = aApps[id];
-      if (app.manifestURL == aManifestURL) {
-        return new mozIApplication(app);
-      }
-    }
-
-    return null;
-  },
-
   getManifestFor: function getManifestFor(aManifestURL) {
     debug("getManifestFor(" + aManifestURL + ")");
     return DOMApplicationRegistry.getManifestFor(aManifestURL);
@@ -259,18 +200,6 @@ this.AppsUtils = {
     return Ci.nsIScriptSecurityManager.NO_APP_ID;
   },
 
-  getAppByLocalId: function getAppByLocalId(aApps, aLocalId) {
-    debug("getAppByLocalId " + aLocalId);
-    for (let id in aApps) {
-      let app = aApps[id];
-      if (app.localId == aLocalId) {
-        return new mozIApplication(app);
-      }
-    }
-
-    return null;
-  },
-
   getManifestURLByLocalId: function getManifestURLByLocalId(aApps, aLocalId) {
     debug("getManifestURLByLocalId " + aLocalId);
     for (let id in aApps) {
@@ -697,14 +626,6 @@ this.AppsUtils = {
     return this.computeHash(JSON.stringify(aObject));
   },
 
-  getAppManifestURLFromWindow: function(aWindow) {
-    let appId = aWindow.document.nodePrincipal.appId;
-    if (appId === Ci.nsIScriptSecurityManager.NO_APP_ID) {
-      return null;
-    }
-
-    return appsService.getManifestURLByLocalId(appId);
-  },
 }
 
 /**
diff --git a/dom/apps/PermissionsTable.jsm b/dom/apps/PermissionsTable.jsm
index 7c6a8490fc..550d73d6c7 100644
--- a/dom/apps/PermissionsTable.jsm
+++ b/dom/apps/PermissionsTable.jsm
@@ -233,11 +233,6 @@ this.PermissionsTable =  { geolocation: {
                              privileged: DENY_ACTION,
                              certified: ALLOW_ACTION
                            },
-                           "embed-apps": {
-                             app: DENY_ACTION,
-                             privileged: DENY_ACTION,
-                             certified: ALLOW_ACTION
-                           },
                            "background-sensors": {
                              app: DENY_ACTION,
                              privileged: DENY_ACTION,
diff --git a/dom/apps/moz.build b/dom/apps/moz.build
index 27ac62947e..d16c926bc7 100644
--- a/dom/apps/moz.build
+++ b/dom/apps/moz.build
@@ -5,13 +5,7 @@
 
 XPCSHELL_TESTS_MANIFESTS += ['tests/unit/xpcshell.ini']
 
-EXTRA_COMPONENTS += [
-    'AppsService.js',
-    'AppsService.manifest',
-]
-
 EXTRA_JS_MODULES += [
-    'AppsServiceChild.jsm',
     'AppsUtils.jsm',
     'PermissionsInstaller.jsm',
     'PermissionsTable.jsm',
diff --git a/dom/apps/tests/unit/test_moziapplication.js b/dom/apps/tests/unit/test_moziapplication.js
deleted file mode 100644
index dbcf2372a3..0000000000
--- a/dom/apps/tests/unit/test_moziapplication.js
+++ /dev/null
@@ -1,64 +0,0 @@
-/* Any copyright is dedicated to the Public Domain.
-   http://creativecommons.org/publicdomain/zero/1.0/ */
-
-var {classes: Cc, interfaces: Ci, utils: Cu} = Components;
-
-Cu.import("resource:///modules/AppsUtils.jsm");
-
-add_test(() => {
-  let app = {
-    name: "TestApp",
-    csp: "aCsp",
-    installOrigin: "http://installorigin.com",
-    origin: "http://www.example.com",
-    installTime: Date.now(),
-    manifestURL: "http://www.example.com/manifest.webapp",
-    appStatus: Ci.nsIPrincipal.APP_STATUS_NOT_INSTALLED,
-    removable: false,
-    id: 123,
-    localId: 123,
-    basePath: "/",
-    progress: 1.0,
-    installState: "installed",
-    downloadAvailable: false,
-    downloading: false,
-    lastUpdateCheck: Date.now(),
-    updateTime: Date.now(),
-    etag: "aEtag",
-    packageEtag: "aPackageEtag",
-    manifestHash: "aManifestHash",
-    packageHash: "aPackageHash",
-    staged: false,
-    installerAppId: 345,
-    installerIsBrowser: false,
-    storeId: "aStoreId",
-    storeVersion: 1,
-    role: "aRole",
-    kind: "aKind",
-    enabled: true,
-    sideloaded: false
-  };
-
-  let mozapp = new mozIApplication(app);
-
-  Object.keys(app).forEach((key) => {
-    if (key == "principal") {
-      return;
-    }
-    Assert.equal(app[key], mozapp[key],
-                 "app[" + key + "] should be equal to mozapp[" + key + "]");
-  });
-
-  Assert.ok(mozapp.principal, "app principal should exist");
-  let expectedPrincipalOrigin = app.origin + "^appId=" + app.localId;
-  Assert.equal(mozapp.principal.origin, expectedPrincipalOrigin,
-               "app principal origin ok");
-  Assert.equal(mozapp.principal.appId, app.localId, "app principal appId ok");
-  Assert.equal(mozapp.principal.isInIsolatedMozBrowserElement, false,
-               "app principal isInIsolatedMozBrowserElement ok");
-  run_next_test();
-});
-
-function run_test() {
-  run_next_test();
-}
diff --git a/dom/apps/tests/unit/xpcshell.ini b/dom/apps/tests/unit/xpcshell.ini
index 9745b198f2..c7df08d02d 100644
--- a/dom/apps/tests/unit/xpcshell.ini
+++ b/dom/apps/tests/unit/xpcshell.ini
@@ -2,4 +2,3 @@
 
 [test_manifestSanitizer.js]
 [test_manifestHelper.js]
-[test_moziapplication.js]
diff --git a/dom/asmjscache/AsmJSCache.cpp b/dom/asmjscache/AsmJSCache.cpp
index 16faebc1d2..4eae09d2ad 100644
--- a/dom/asmjscache/AsmJSCache.cpp
+++ b/dom/asmjscache/AsmJSCache.cpp
@@ -30,7 +30,6 @@
 #include "nsIAtom.h"
 #include "nsIFile.h"
 #include "nsIIPCBackgroundChildCreateCallback.h"
-#include "nsIPermissionManager.h"
 #include "nsIPrincipal.h"
 #include "nsIRunnable.h"
 #include "nsISimpleEnumerator.h"
@@ -443,11 +442,9 @@ public:
     mPrincipalInfo(aPrincipalInfo),
     mOpenMode(aOpenMode),
     mWriteParams(aWriteParams),
-    mPersistence(quota::PERSISTENCE_TYPE_INVALID),
     mState(eInitial),
     mResult(JS::AsmJSCache_InternalError),
-    mIsApp(false),
-    mEnforcingQuota(true),
+    mDeleteReceived(false),
     mActorDestroyed(false),
     mOpened(false)
   {
@@ -488,31 +485,6 @@ private:
     MOZ_ASSERT(!IsOnOwningThread());
   }
 
-  // This method is called on the owning thread when no cache entry was found
-  // to open. If we just tried a lookup in persistent storage then we might
-  // still get a hit in temporary storage (for an asm.js module that wasn't
-  // compiled at install-time).
-  void
-  CacheMiss()
-  {
-    AssertIsOnOwningThread();
-    MOZ_ASSERT(mState == eFailedToReadMetadata ||
-               mState == eWaitingToOpenCacheFileForRead);
-    MOZ_ASSERT(mOpenMode == eOpenForRead);
-
-    if (mPersistence == quota::PERSISTENCE_TYPE_TEMPORARY) {
-      Fail();
-      return;
-    }
-
-    // Try again with a clean slate. InitOnMainThread will see that mPersistence
-    // is initialized and switch to temporary storage.
-    MOZ_ASSERT(mPersistence == quota::PERSISTENCE_TYPE_PERSISTENT);
-    FinishOnOwningThread();
-    mState = eInitial;
-    NS_DispatchToMainThread(this);
-  }
-
   // This method is called on the owning thread when the JS engine is finished
   // reading/writing the cache entry.
   void
@@ -542,7 +514,7 @@ private:
 
     FinishOnOwningThread();
 
-    if (!mActorDestroyed) {
+    if (!mDeleteReceived && !mActorDestroyed) {
       Unused << Send__delete__(this, mResult);
     }
   }
@@ -561,9 +533,6 @@ private:
     MOZ_ALWAYS_SUCCEEDS(mOwningThread->Dispatch(this, NS_DISPATCH_NORMAL));
   }
 
-  void
-  InitPersistenceType();
-
   nsresult
   InitOnMainThread();
 
@@ -615,6 +584,10 @@ private:
     AssertIsOnOwningThread();
     MOZ_ASSERT(mState != eFinished);
 
+    MOZ_ASSERT(!mDeleteReceived);
+
+    mDeleteReceived = true;
+
     if (mOpened) {
       Close();
     } else {
@@ -666,23 +639,12 @@ private:
     return true;
   }
 
-  bool
-  RecvCacheMiss() override
-  {
-    AssertIsOnOwningThread();
-
-    CacheMiss();
-
-    return true;
-  }
-
   nsCOMPtr<nsIEventTarget> mOwningThread;
   const PrincipalInfo mPrincipalInfo;
   const OpenMode mOpenMode;
   const WriteParams mWriteParams;
 
   // State initialized during eInitial:
-  quota::PersistenceType mPersistence;
   nsCString mSuffix;
   nsCString mGroup;
   nsCString mOrigin;
@@ -702,7 +664,6 @@ private:
     eWaitingToOpenDirectory, // Waiting to open directory
     eWaitingToOpenMetadata, // Waiting to be called back from OpenDirectory
     eReadyToReadMetadata, // Waiting to read the metadata file on the IO thread
-    eFailedToReadMetadata, // Waiting to be dispatched to owning thread after fail
     eSendingMetadataForRead, // Waiting to send OnOpenMetadataForRead
     eWaitingToOpenCacheFileForRead, // Waiting to hear back from child
     eReadyToOpenCacheFileForRead, // Waiting to open cache file for read
@@ -714,58 +675,11 @@ private:
   State mState;
   JS::AsmJSCacheResult mResult;
 
-  bool mIsApp;
-  bool mEnforcingQuota;
+  bool mDeleteReceived;
   bool mActorDestroyed;
   bool mOpened;
 };
 
-void
-ParentRunnable::InitPersistenceType()
-{
-  MOZ_ASSERT(NS_IsMainThread());
-  MOZ_ASSERT(mState == eInitial);
-
-  if (mOpenMode == eOpenForWrite) {
-    MOZ_ASSERT(mPersistence == quota::PERSISTENCE_TYPE_INVALID);
-
-    // If we are performing install-time caching of an app, we'd like to store
-    // the cache entry in persistent storage so the entry is never evicted,
-    // but we need to check that quota is not enforced for the app.
-    // That justifies us in skipping all quota checks when storing the cache
-    // entry and avoids all the issues around the persistent quota prompt.
-    // If quota is enforced for the app, then we can still cache in temporary
-    // for a likely good first-run experience.
-
-    MOZ_ASSERT_IF(mWriteParams.mInstalled, mIsApp);
-
-    if (mWriteParams.mInstalled &&
-        !QuotaManager::IsQuotaEnforced(quota::PERSISTENCE_TYPE_PERSISTENT,
-                                       mOrigin, mIsApp)) {
-      mPersistence = quota::PERSISTENCE_TYPE_PERSISTENT;
-    } else {
-      mPersistence = quota::PERSISTENCE_TYPE_TEMPORARY;
-    }
-
-    return;
-  }
-
-  // For the reasons described above, apps may have cache entries in both
-  // persistent and temporary storage. At lookup time we don't know how and
-  // where the given script was cached, so start the search in persistent
-  // storage and, if that fails, search in temporary storage. (Non-apps can
-  // only be stored in temporary storage.)
-
-  MOZ_ASSERT_IF(mPersistence != quota::PERSISTENCE_TYPE_INVALID,
-                mIsApp && mPersistence == quota::PERSISTENCE_TYPE_PERSISTENT);
-
-  if (mPersistence == quota::PERSISTENCE_TYPE_INVALID && mIsApp) {
-    mPersistence = quota::PERSISTENCE_TYPE_PERSISTENT;
-  } else {
-    mPersistence = quota::PERSISTENCE_TYPE_TEMPORARY;
-  }
-}
-
 nsresult
 ParentRunnable::InitOnMainThread()
 {
@@ -780,15 +694,9 @@ ParentRunnable::InitOnMainThread()
     return rv;
   }
 
-  rv = QuotaManager::GetInfoFromPrincipal(principal, &mSuffix, &mGroup,
-                                          &mOrigin, &mIsApp);
+  rv = QuotaManager::GetInfoFromPrincipal(principal, &mSuffix, &mGroup, &mOrigin);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  InitPersistenceType();
-
-  mEnforcingQuota =
-    QuotaManager::IsQuotaEnforced(mPersistence, mOrigin, mIsApp);
-
   return NS_OK;
 }
 
@@ -803,10 +711,9 @@ ParentRunnable::OpenDirectory()
   mState = eWaitingToOpenMetadata;
 
   // XXX The exclusive lock shouldn't be needed for read operations.
-  QuotaManager::Get()->OpenDirectory(mPersistence,
+  QuotaManager::Get()->OpenDirectory(quota::PERSISTENCE_TYPE_TEMPORARY,
                                      mGroup,
                                      mOrigin,
-                                     mIsApp,
                                      quota::Client::ASMJS,
                                      /* aExclusive */ true,
                                      this);
@@ -822,8 +729,11 @@ ParentRunnable::ReadMetadata()
   MOZ_ASSERT(qm, "We are on the QuotaManager's IO thread");
 
   nsresult rv =
-    qm->EnsureOriginIsInitialized(mPersistence, mSuffix, mGroup, mOrigin,
-                                  mIsApp, getter_AddRefs(mDirectory));
+    qm->EnsureOriginIsInitialized(quota::PERSISTENCE_TYPE_TEMPORARY,
+                                  mSuffix,
+                                  mGroup,
+                                  mOrigin,
+                                  getter_AddRefs(mDirectory));
   if (NS_WARN_IF(NS_FAILED(rv))) {
     mResult = JS::AsmJSCache_StorageInitFailure;
     return rv;
@@ -894,25 +804,23 @@ ParentRunnable::OpenCacheFileForWrite()
   QuotaManager* qm = QuotaManager::Get();
   MOZ_ASSERT(qm, "We are on the QuotaManager's IO thread");
 
-  if (mEnforcingQuota) {
-    // Create the QuotaObject before all file IO and keep it alive until caching
-    // completes to get maximum assertion coverage in QuotaManager against
-    // concurrent removal, etc.
-    mQuotaObject = qm->GetQuotaObject(mPersistence, mGroup, mOrigin, file);
-    NS_ENSURE_STATE(mQuotaObject);
+  // Create the QuotaObject before all file IO and keep it alive until caching
+  // completes to get maximum assertion coverage in QuotaManager against
+  // concurrent removal, etc.
+  mQuotaObject = qm->GetQuotaObject(quota::PERSISTENCE_TYPE_TEMPORARY, mGroup, mOrigin, file);
+  NS_ENSURE_STATE(mQuotaObject);
 
+  if (!mQuotaObject->MaybeUpdateSize(mWriteParams.mSize,
+                                     /* aTruncate */ false)) {
+    // If the request fails, it might be because mOrigin is using too much
+    // space (MaybeUpdateSize will not evict our own origin since it is
+    // active). Try to make some space by evicting LRU entries until there is
+    // enough space.
+    EvictEntries(mDirectory, mGroup, mOrigin, mWriteParams.mSize, mMetadata);
     if (!mQuotaObject->MaybeUpdateSize(mWriteParams.mSize,
                                        /* aTruncate */ false)) {
-      // If the request fails, it might be because mOrigin is using too much
-      // space (MaybeUpdateSize will not evict our own origin since it is
-      // active). Try to make some space by evicting LRU entries until there is
-      // enough space.
-      EvictEntries(mDirectory, mGroup, mOrigin, mWriteParams.mSize, mMetadata);
-      if (!mQuotaObject->MaybeUpdateSize(mWriteParams.mSize,
-                                         /* aTruncate */ false)) {
-        mResult = JS::AsmJSCache_QuotaExceeded;
-        return NS_ERROR_FAILURE;
-      }
+      mResult = JS::AsmJSCache_QuotaExceeded;
+      return NS_ERROR_FAILURE;
     }
   }
 
@@ -948,13 +856,11 @@ ParentRunnable::OpenCacheFileForRead()
   QuotaManager* qm = QuotaManager::Get();
   MOZ_ASSERT(qm, "We are on the QuotaManager's IO thread");
 
-  if (mEnforcingQuota) {
-    // Even though it's not strictly necessary, create the QuotaObject before
-    // all file IO and keep it alive until caching completes to get maximum
-    // assertion coverage in QuotaManager against concurrent removal, etc.
-    mQuotaObject = qm->GetQuotaObject(mPersistence, mGroup, mOrigin, file);
-    NS_ENSURE_STATE(mQuotaObject);
-  }
+  // Even though it's not strictly necessary, create the QuotaObject before
+  // all file IO and keep it alive until caching completes to get maximum
+  // assertion coverage in QuotaManager against concurrent removal, etc.
+  mQuotaObject = qm->GetQuotaObject(quota::PERSISTENCE_TYPE_TEMPORARY, mGroup, mOrigin, file);
+  NS_ENSURE_STATE(mQuotaObject);
 
   rv = file->GetFileSize(&mFileSize);
   NS_ENSURE_SUCCESS(rv, rv);
@@ -1058,8 +964,7 @@ ParentRunnable::Run()
 
       rv = ReadMetadata();
       if (NS_FAILED(rv)) {
-        mState = eFailedToReadMetadata;
-        MOZ_ALWAYS_SUCCEEDS(mOwningThread->Dispatch(this, NS_DISPATCH_NORMAL));
+        FailOnNonOwningThread();
         return NS_OK;
       }
 
@@ -1081,18 +986,6 @@ ParentRunnable::Run()
       return NS_OK;
     }
 
-    case eFailedToReadMetadata: {
-      AssertIsOnOwningThread();
-
-      if (mOpenMode == eOpenForRead) {
-        CacheMiss();
-        return NS_OK;
-      }
-
-      Fail();
-      return NS_OK;
-    }
-
     case eSendingMetadataForRead: {
       AssertIsOnOwningThread();
       MOZ_ASSERT(mOpenMode == eOpenForRead);
@@ -1404,11 +1297,13 @@ private:
     MOZ_ASSERT(mState == eOpening);
 
     uint32_t moduleIndex;
-    if (FindHashMatch(aMetadata, mReadParams, &moduleIndex)) {
-      return SendSelectCacheFileToRead(moduleIndex);
+    if (!FindHashMatch(aMetadata, mReadParams, &moduleIndex)) {
+      Fail(JS::AsmJSCache_InternalError);
+      Send__delete__(this, JS::AsmJSCache_InternalError);
+      return true;
     }
 
-    return SendCacheMiss();
+    return SendSelectCacheFileToRead(moduleIndex);
   }
 
   bool
@@ -1760,7 +1655,6 @@ CloseEntryForRead(size_t aSize,
 
 JS::AsmJSCacheResult
 OpenEntryForWrite(nsIPrincipal* aPrincipal,
-                  bool aInstalled,
                   const char16_t* aBegin,
                   const char16_t* aEnd,
                   size_t aSize,
@@ -1777,7 +1671,6 @@ OpenEntryForWrite(nsIPrincipal* aPrincipal,
   static_assert(sNumFastHashChars < sMinCachedModuleLength, "HashString safe");
 
   WriteParams writeParams;
-  writeParams.mInstalled = aInstalled;
   writeParams.mSize = aSize;
   writeParams.mFastHash = HashString(aBegin, sNumFastHashChars);
   writeParams.mNumChars = aEnd - aBegin;
@@ -2043,7 +1936,6 @@ ParamTraits<WriteParams>::Write(Message* aMsg, const paramType& aParam)
   WriteParam(aMsg, aParam.mFastHash);
   WriteParam(aMsg, aParam.mNumChars);
   WriteParam(aMsg, aParam.mFullHash);
-  WriteParam(aMsg, aParam.mInstalled);
 }
 
 bool
@@ -2053,8 +1945,7 @@ ParamTraits<WriteParams>::Read(const Message* aMsg, PickleIterator* aIter,
   return ReadParam(aMsg, aIter, &aResult->mSize) &&
          ReadParam(aMsg, aIter, &aResult->mFastHash) &&
          ReadParam(aMsg, aIter, &aResult->mNumChars) &&
-         ReadParam(aMsg, aIter, &aResult->mFullHash) &&
-         ReadParam(aMsg, aIter, &aResult->mInstalled);
+         ReadParam(aMsg, aIter, &aResult->mFullHash);
 }
 
 void
@@ -2064,7 +1955,6 @@ ParamTraits<WriteParams>::Log(const paramType& aParam, std::wstring* aLog)
   LogParam(aParam.mFastHash, aLog);
   LogParam(aParam.mNumChars, aLog);
   LogParam(aParam.mFullHash, aLog);
-  LogParam(aParam.mInstalled, aLog);
 }
 
 } // namespace IPC
diff --git a/dom/asmjscache/AsmJSCache.h b/dom/asmjscache/AsmJSCache.h
index 45ef1f2b5f..eb2dbe2241 100644
--- a/dom/asmjscache/AsmJSCache.h
+++ b/dom/asmjscache/AsmJSCache.h
@@ -72,14 +72,12 @@ struct WriteParams
   int64_t mFastHash;
   int64_t mNumChars;
   int64_t mFullHash;
-  bool mInstalled;
 
   WriteParams()
-  : mSize(0),
-    mFastHash(0),
-    mNumChars(0),
-    mFullHash(0),
-    mInstalled(false)
+  : mSize(0)
+  , mFastHash(0)
+  , mNumChars(0)
+  , mFullHash(0)
   { }
 };
 
@@ -90,8 +88,8 @@ struct ReadParams
   const char16_t* mLimit;
 
   ReadParams()
-  : mBegin(nullptr),
-    mLimit(nullptr)
+  : mBegin(nullptr)
+  , mLimit(nullptr)
   { }
 };
 
@@ -120,7 +118,6 @@ CloseEntryForRead(size_t aSize,
                   intptr_t aHandle);
 JS::AsmJSCacheResult
 OpenEntryForWrite(nsIPrincipal* aPrincipal,
-                  bool aInstalled,
                   const char16_t* aBegin,
                   const char16_t* aEnd,
                   size_t aSize,
diff --git a/dom/asmjscache/PAsmJSCacheEntry.ipdl b/dom/asmjscache/PAsmJSCacheEntry.ipdl
index 4980650ccb..d16c9284ff 100644
--- a/dom/asmjscache/PAsmJSCacheEntry.ipdl
+++ b/dom/asmjscache/PAsmJSCacheEntry.ipdl
@@ -22,7 +22,6 @@ child:
   async OnOpenMetadataForRead(Metadata metadata);
 parent:
   async SelectCacheFileToRead(uint32_t moduleIndex);
-  async CacheMiss();
 
 child:
   // Once the cache file has been opened, the child is notified and sent an
diff --git a/dom/base/Navigator.cpp b/dom/base/Navigator.cpp
index 026ae15836..26789c2881 100644
--- a/dom/base/Navigator.cpp
+++ b/dom/base/Navigator.cpp
@@ -62,8 +62,6 @@
 #include "nsIHttpChannelInternal.h"
 #include "TimeManager.h"
 #include "nsStreamUtils.h"
-#include "nsIAppsService.h"
-#include "mozIApplication.h"
 #include "WidgetUtils.h"
 #include "mozilla/dom/MediaDevices.h"
 #include "MediaManager.h"
diff --git a/dom/base/ThirdPartyUtil.cpp b/dom/base/ThirdPartyUtil.cpp
index 8c0ba80bf8..39f72eb546 100644
--- a/dom/base/ThirdPartyUtil.cpp
+++ b/dom/base/ThirdPartyUtil.cpp
@@ -17,6 +17,7 @@
 #include "nsIURI.h"
 #include "nsThreadUtils.h"
 #include "mozilla/Logging.h"
+#include "nsPIDOMWindow.h"
 
 NS_IMPL_ISUPPORTS(ThirdPartyUtil, mozIThirdPartyUtil)
 
@@ -145,7 +146,7 @@ ThirdPartyUtil::IsThirdPartyWindow(mozIDOMWindowProxy* aWindow,
   nsCOMPtr<nsIURI> parentURI;
   do {
     // We use GetScriptableParent rather than GetParent because we consider
-    // <iframe mozbrowser/mozapp> to be a top-level frame.
+    // <iframe mozbrowser> to be a top-level frame.
     parent = current->GetScriptableParent();
     if (SameCOMIdentity(parent, current)) {
       // We're at the topmost content window. We already know the answer.
diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
index 5d5edbd3b3..155d55ac29 100644
--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -6616,7 +6616,7 @@ nsContentUtils::IsUserFocusIgnored(nsINode* aNode)
     nsCOMPtr<nsIMozBrowserFrame> browserFrame = do_QueryInterface(aNode);
     if (browserFrame &&
         aNode->AsElement()->HasAttr(kNameSpaceID_None, nsGkAtoms::ignoreuserfocus) &&
-        browserFrame->GetReallyIsBrowserOrApp()) {
+        browserFrame->GetReallyIsBrowser()) {
       return true;
     }
     nsPIDOMWindowOuter* win = aNode->OwnerDoc()->GetWindow();
diff --git a/dom/base/nsDOMWindowUtils.cpp b/dom/base/nsDOMWindowUtils.cpp
index 18204efdc1..37e9018fa0 100644
--- a/dom/base/nsDOMWindowUtils.cpp
+++ b/dom/base/nsDOMWindowUtils.cpp
@@ -3026,8 +3026,7 @@ nsDOMWindowUtils::GetFileReferences(const nsAString& aDatabaseName, int64_t aId,
 
   nsCString origin;
   nsresult rv =
-    quota::QuotaManager::GetInfoFromWindow(window, nullptr, nullptr, &origin,
-                                           nullptr);
+    quota::QuotaManager::GetInfoFromWindow(window, nullptr, nullptr, &origin);
   NS_ENSURE_SUCCESS(rv, rv);
 
   IDBOpenDBOptions options;
diff --git a/dom/base/nsFrameLoader.cpp b/dom/base/nsFrameLoader.cpp
index 33ddb08109..ee030abf24 100644
--- a/dom/base/nsFrameLoader.cpp
+++ b/dom/base/nsFrameLoader.cpp
@@ -12,9 +12,7 @@
 
 #include "prenv.h"
 
-#include "mozIApplication.h"
 #include "nsDocShell.h"
-#include "nsIAppsService.h"
 #include "nsIDOMHTMLIFrameElement.h"
 #include "nsIDOMHTMLFrameElement.h"
 #include "nsIDOMMozBrowserFrame.h"
@@ -88,7 +86,6 @@
 #include "mozilla/dom/Element.h"
 #include "mozilla/jsipc/CrossProcessObjectWrappers.h"
 #include "mozilla/layout/RenderFrameParent.h"
-#include "nsIAppsService.h"
 #include "GeckoProfiler.h"
 
 #include "jsapi.h"
@@ -1071,12 +1068,6 @@ nsFrameLoader::SwapWithOtherRemoteLoader(nsFrameLoader* aOther,
     return NS_ERROR_NOT_IMPLEMENTED;
   }
 
-  if (mRemoteBrowser->IsIsolatedMozBrowserElement() !=
-      aOther->mRemoteBrowser->IsIsolatedMozBrowserElement() ||
-      mRemoteBrowser->HasOwnApp() != aOther->mRemoteBrowser->HasOwnApp()) {
-    return NS_ERROR_NOT_IMPLEMENTED;
-  }
-
   // When we swap docShells, maybe we have to deal with a new page created just
   // for this operation. In this case, the browser code should already have set
   // the correct userContextId attribute value in the owning XULElement, but our
@@ -1145,10 +1136,10 @@ nsFrameLoader::SwapWithOtherRemoteLoader(nsFrameLoader* aOther,
   }
 
   // Destroy browser frame scripts for content leaving a frame with browser API
-  if (OwnerIsMozBrowserOrAppFrame() && !aOther->OwnerIsMozBrowserOrAppFrame()) {
+  if (OwnerIsMozBrowserFrame() && !aOther->OwnerIsMozBrowserFrame()) {
     DestroyBrowserFrameScripts();
   }
-  if (!OwnerIsMozBrowserOrAppFrame() && aOther->OwnerIsMozBrowserOrAppFrame()) {
+  if (!OwnerIsMozBrowserFrame() && aOther->OwnerIsMozBrowserFrame()) {
     aOther->DestroyBrowserFrameScripts();
   }
 
@@ -1320,12 +1311,12 @@ nsFrameLoader::SwapWithOtherLoader(nsFrameLoader* aOther,
 
   bool ourFullscreenAllowed =
     ourContent->IsXULElement() ||
-    (OwnerIsMozBrowserOrAppFrame() &&
+    (OwnerIsMozBrowserFrame() &&
       (ourContent->HasAttr(kNameSpaceID_None, nsGkAtoms::allowfullscreen) ||
        ourContent->HasAttr(kNameSpaceID_None, nsGkAtoms::mozallowfullscreen)));
   bool otherFullscreenAllowed =
     otherContent->IsXULElement() ||
-    (aOther->OwnerIsMozBrowserOrAppFrame() &&
+    (aOther->OwnerIsMozBrowserFrame() &&
       (otherContent->HasAttr(kNameSpaceID_None, nsGkAtoms::allowfullscreen) ||
        otherContent->HasAttr(kNameSpaceID_None, nsGkAtoms::mozallowfullscreen)));
   if (ourFullscreenAllowed != otherFullscreenAllowed) {
@@ -1470,12 +1461,6 @@ nsFrameLoader::SwapWithOtherLoader(nsFrameLoader* aOther,
     return NS_ERROR_NOT_IMPLEMENTED;
   }
 
-  if (ourDocshell->GetIsIsolatedMozBrowserElement() !=
-      otherDocshell->GetIsIsolatedMozBrowserElement() ||
-      ourDocshell->GetIsApp() != otherDocshell->GetIsApp()) {
-    return NS_ERROR_NOT_IMPLEMENTED;
-  }
-
   // When we swap docShells, maybe we have to deal with a new page created just
   // for this operation. In this case, the browser code should already have set
   // the correct userContextId attribute value in the owning XULElement, but our
@@ -1522,10 +1507,10 @@ nsFrameLoader::SwapWithOtherLoader(nsFrameLoader* aOther,
   }
 
   // Destroy browser frame scripts for content leaving a frame with browser API
-  if (OwnerIsMozBrowserOrAppFrame() && !aOther->OwnerIsMozBrowserOrAppFrame()) {
+  if (OwnerIsMozBrowserFrame() && !aOther->OwnerIsMozBrowserFrame()) {
     DestroyBrowserFrameScripts();
   }
-  if (!OwnerIsMozBrowserOrAppFrame() && aOther->OwnerIsMozBrowserOrAppFrame()) {
+  if (!OwnerIsMozBrowserFrame() && aOther->OwnerIsMozBrowserFrame()) {
     aOther->DestroyBrowserFrameScripts();
   }
 
@@ -1884,102 +1869,20 @@ nsFrameLoader::SetOwnerContent(Element* aContent)
 }
 
 bool
-nsFrameLoader::OwnerIsMozBrowserOrAppFrame()
+nsFrameLoader::OwnerIsMozBrowserFrame()
 {
   nsCOMPtr<nsIMozBrowserFrame> browserFrame = do_QueryInterface(mOwnerContent);
-  return browserFrame ? browserFrame->GetReallyIsBrowserOrApp() : false;
+  return browserFrame ? browserFrame->GetReallyIsBrowser() : false;
 }
 
 // The xpcom getter version
 NS_IMETHODIMP
-nsFrameLoader::GetOwnerIsMozBrowserOrAppFrame(bool* aResult)
+nsFrameLoader::GetOwnerIsMozBrowserFrame(bool* aResult)
 {
-  *aResult = OwnerIsMozBrowserOrAppFrame();
+  *aResult = OwnerIsMozBrowserFrame();
   return NS_OK;
 }
 
-bool
-nsFrameLoader::OwnerIsAppFrame()
-{
-  nsCOMPtr<nsIMozBrowserFrame> browserFrame = do_QueryInterface(mOwnerContent);
-  return browserFrame ? browserFrame->GetReallyIsApp() : false;
-}
-
-bool
-nsFrameLoader::OwnerIsMozBrowserFrame()
-{
-  return OwnerIsMozBrowserOrAppFrame() && !OwnerIsAppFrame();
-}
-
-bool
-nsFrameLoader::OwnerIsIsolatedMozBrowserFrame()
-{
-  nsCOMPtr<nsIMozBrowserFrame> browserFrame = do_QueryInterface(mOwnerContent);
-  if (!browserFrame) {
-    return false;
-  }
-
-  if (!OwnerIsMozBrowserFrame()) {
-    return false;
-  }
-
-  bool isolated = browserFrame->GetIsolated();
-  if (isolated) {
-    return true;
-  }
-
-  return false;
-}
-
-void
-nsFrameLoader::GetOwnerAppManifestURL(nsAString& aOut)
-{
-  aOut.Truncate();
-  nsCOMPtr<nsIMozBrowserFrame> browserFrame = do_QueryInterface(mOwnerContent);
-  if (browserFrame) {
-    browserFrame->GetAppManifestURL(aOut);
-  }
-}
-
-already_AddRefed<mozIApplication>
-nsFrameLoader::GetOwnApp()
-{
-  nsAutoString manifest;
-  GetOwnerAppManifestURL(manifest);
-  if (manifest.IsEmpty()) {
-    return nullptr;
-  }
-
-  nsCOMPtr<nsIAppsService> appsService = do_GetService(APPS_SERVICE_CONTRACTID);
-  NS_ENSURE_TRUE(appsService, nullptr);
-
-  nsCOMPtr<mozIApplication> app;
-  appsService->GetAppByManifestURL(manifest, getter_AddRefs(app));
-
-  return app.forget();
-}
-
-already_AddRefed<mozIApplication>
-nsFrameLoader::GetContainingApp()
-{
-  // See if our owner content's principal has an associated app.
-  uint32_t appId = mOwnerContent->NodePrincipal()->GetAppId();
-  MOZ_ASSERT(appId != nsIScriptSecurityManager::UNKNOWN_APP_ID);
-
-  if (appId == nsIScriptSecurityManager::NO_APP_ID ||
-      appId == nsIScriptSecurityManager::UNKNOWN_APP_ID) {
-    return nullptr;
-  }
-
-  nsCOMPtr<nsIAppsService> appsService = do_GetService(APPS_SERVICE_CONTRACTID);
-  NS_ENSURE_TRUE(appsService, nullptr);
-
-  nsCOMPtr<mozIApplication> app;
-  appsService->GetAppByLocalId(appId, getter_AddRefs(app));
-
-  return app.forget();
-}
-
 bool
 nsFrameLoader::ShouldUseRemoteProcess()
 {
@@ -2003,7 +1906,7 @@ nsFrameLoader::ShouldUseRemoteProcess()
 
   // If we're an <iframe mozbrowser> and we don't have a "remote" attribute,
   // fall back to the default.
-  if (OwnerIsMozBrowserOrAppFrame() &&
+  if (OwnerIsMozBrowserFrame() &&
       !mOwnerContent->HasAttr(kNameSpaceID_None, nsGkAtoms::Remote)) {
 
     return Preferences::GetBool("dom.ipc.browser_frames.oop_by_default", false);
@@ -2011,7 +1914,7 @@ nsFrameLoader::ShouldUseRemoteProcess()
 
   // Otherwise, we're remote if we have "remote=true" and we're either a
   // browser frame or a XUL element.
-  return (OwnerIsMozBrowserOrAppFrame() ||
+  return (OwnerIsMozBrowserFrame() ||
           mOwnerContent->GetNameSpaceID() == kNameSpaceID_XUL) &&
          mOwnerContent->AttrValueIs(kNameSpaceID_None,
                                     nsGkAtoms::Remote,
@@ -2189,13 +2092,13 @@ nsFrameLoader::MaybeCreateDocShell()
   // Inherit origin attributes from parent document if
   // 1. It's in a content docshell.
   // 2. its nodePrincipal is not a SystemPrincipal.
-  // 3. It's not a mozbrowser nor mozapp frame.
+  // 3. It's not a mozbrowser frame.
   //
   // For example, firstPartyDomain is computed from top-level document, it
   // doesn't exist in the top-level docshell.
   if (parentType == nsIDocShellTreeItem::typeContent &&
       !nsContentUtils::IsSystemPrincipal(doc->NodePrincipal()) &&
-      !OwnerIsMozBrowserOrAppFrame()) {
+      !OwnerIsMozBrowserFrame()) {
     PrincipalOriginAttributes poa = BasePrincipal::Cast(doc->NodePrincipal())->OriginAttributesRef();
 
     // Assert on the firstPartyDomain from top-level docshell should be empty
@@ -2210,42 +2113,14 @@ nsFrameLoader::MaybeCreateDocShell()
               "docshell and document should have the same appId attribute.");
     MOZ_ASSERT(attrs.mUserContextId == poa.mUserContextId,
               "docshell and document should have the same userContextId attribute.");
-    MOZ_ASSERT(attrs.mInIsolatedMozBrowser == poa.mInIsolatedMozBrowser,
-              "docshell and document should have the same inIsolatedMozBrowser attribute.");
     MOZ_ASSERT(attrs.mPrivateBrowsingId == poa.mPrivateBrowsingId,
               "docshell and document should have the same privateBrowsingId attribute.");
 
     attrs.InheritFromDocToChildDocShell(poa);
   }
 
-  if (OwnerIsAppFrame()) {
-    // You can't be both an app and a browser frame.
-    MOZ_ASSERT(!OwnerIsMozBrowserFrame());
-
-    nsCOMPtr<mozIApplication> ownApp = GetOwnApp();
-    MOZ_ASSERT(ownApp);
-    uint32_t ownAppId = nsIScriptSecurityManager::NO_APP_ID;
-    if (ownApp) {
-      NS_ENSURE_SUCCESS(ownApp->GetLocalId(&ownAppId), NS_ERROR_FAILURE);
-    }
-
-    attrs.mAppId = ownAppId;
-    mDocShell->SetFrameType(nsIDocShell::FRAME_TYPE_APP);
-  }
-
   if (OwnerIsMozBrowserFrame()) {
-    // You can't be both a browser and an app frame.
-    MOZ_ASSERT(!OwnerIsAppFrame());
-
-    nsCOMPtr<mozIApplication> containingApp = GetContainingApp();
-    uint32_t containingAppId = nsIScriptSecurityManager::NO_APP_ID;
-    if (containingApp) {
-      NS_ENSURE_SUCCESS(containingApp->GetLocalId(&containingAppId),
-                        NS_ERROR_FAILURE);
-    }
-
-    attrs.mAppId = containingAppId;
-    attrs.mInIsolatedMozBrowser = OwnerIsIsolatedMozBrowserFrame();
+    attrs.mAppId = nsIScriptSecurityManager::NO_APP_ID;
     mDocShell->SetFrameType(nsIDocShell::FRAME_TYPE_BROWSER);
   }
 
@@ -2276,7 +2151,7 @@ nsFrameLoader::MaybeCreateDocShell()
   }
   attrs.SyncAttributesWithPrivateBrowsing(isPrivate);
 
-  if (OwnerIsMozBrowserOrAppFrame()) {
+  if (OwnerIsMozBrowserFrame()) {
     // For inproc frames, set the docshell properties.
     nsAutoString name;
     if (mOwnerContent->GetAttr(kNameSpaceID_None, nsGkAtoms::name, name)) {
@@ -2679,7 +2554,7 @@ nsFrameLoader::TryRemoteBrowser()
   }
 
   // <iframe mozbrowser> gets to skip these checks.
-  if (!OwnerIsMozBrowserOrAppFrame()) {
+  if (!OwnerIsMozBrowserFrame()) {
     if (parentDocShell->ItemType() != nsIDocShellTreeItem::typeChrome) {
       return false;
     }
@@ -2720,8 +2595,8 @@ nsFrameLoader::TryRemoteBrowser()
   NS_ENSURE_SUCCESS(rv, false);
 
   nsCOMPtr<Element> ownerElement = mOwnerContent;
-  mRemoteBrowser = ContentParent::CreateBrowserOrApp(context, ownerElement,
-                                                     openerContentParent, mFreshProcess);
+  mRemoteBrowser = ContentParent::CreateBrowser(context, ownerElement,
+                                                openerContentParent, mFreshProcess);
   if (!mRemoteBrowser) {
     return false;
   }
@@ -2984,7 +2859,7 @@ nsFrameLoader::EnsureMessageManager()
   }
 
   if (!mIsTopLevelContent &&
-      !OwnerIsMozBrowserOrAppFrame() &&
+      !OwnerIsMozBrowserFrame() &&
       !IsRemoteFrame() &&
       !(mOwnerContent->IsXULElement() &&
         mOwnerContent->AttrValueIs(kNameSpaceID_None,
@@ -3291,7 +3166,7 @@ nsFrameLoader::GetLoadContext(nsILoadContext** aLoadContext)
 void
 nsFrameLoader::InitializeBrowserAPI()
 {
-  if (!OwnerIsMozBrowserOrAppFrame()) {
+  if (!OwnerIsMozBrowserFrame()) {
     return;
   }
   if (!IsRemoteFrame()) {
@@ -3315,7 +3190,7 @@ nsFrameLoader::InitializeBrowserAPI()
 void
 nsFrameLoader::DestroyBrowserFrameScripts()
 {
-  if (!OwnerIsMozBrowserOrAppFrame()) {
+  if (!OwnerIsMozBrowserFrame()) {
     return;
   }
   nsCOMPtr<nsIMozBrowserFrame> browserFrame = do_QueryInterface(mOwnerContent);
@@ -3396,24 +3271,10 @@ nsresult
 nsFrameLoader::GetNewTabContext(MutableTabContext* aTabContext,
                                 nsIURI* aURI)
 {
-  nsCOMPtr<mozIApplication> ownApp = GetOwnApp();
-  nsCOMPtr<mozIApplication> containingApp = GetContainingApp();
   DocShellOriginAttributes attrs;
-  attrs.mInIsolatedMozBrowser = OwnerIsIsolatedMozBrowserFrame();
   nsresult rv;
 
-  // Get the AppId from ownApp
-  uint32_t appId = nsIScriptSecurityManager::NO_APP_ID;
-  if (ownApp) {
-    rv = ownApp->GetLocalId(&appId);
-    NS_ENSURE_SUCCESS(rv, rv);
-    NS_ENSURE_STATE(appId != nsIScriptSecurityManager::NO_APP_ID);
-  } else if (containingApp) {
-    rv = containingApp->GetLocalId(&appId);
-    NS_ENSURE_SUCCESS(rv, rv);
-    NS_ENSURE_STATE(appId != nsIScriptSecurityManager::NO_APP_ID);
-  }
-  attrs.mAppId = appId;
+  attrs.mAppId = nsIScriptSecurityManager::NO_APP_ID; // No longer used...
 
   // set the userContextId on the attrs before we pass them into
   // the tab context
@@ -3443,8 +3304,6 @@ nsFrameLoader::GetNewTabContext(MutableTabContext* aTabContext,
   bool tabContextUpdated =
     aTabContext->SetTabContext(OwnerIsMozBrowserFrame(),
                                mIsPrerendered,
-                               ownApp,
-                               containingApp,
                                showAccelerators,
                                showFocusRings,
                                attrs);
diff --git a/dom/base/nsFrameLoader.h b/dom/base/nsFrameLoader.h
index 39fb5c1888..900997572e 100644
--- a/dom/base/nsFrameLoader.h
+++ b/dom/base/nsFrameLoader.h
@@ -241,53 +241,18 @@ private:
    */
   bool IsRemoteFrame();
 
-  /**
-   * Is this a frameloader for a bona fide <iframe mozbrowser> or
-   * <iframe mozapp>?  (I.e., does the frame return true for
-   * nsIMozBrowserFrame::GetReallyIsBrowserOrApp()?)
-   * <xul:browser> is not a mozbrowser or app, so this is false for that case.
-   */
-  bool OwnerIsMozBrowserOrAppFrame();
-
-  /**
-   * Is this a frameloader for a bona fide <iframe mozapp>?  (I.e., does the
-   * frame return true for nsIMozBrowserFrame::GetReallyIsApp()?)
-   */
-  bool OwnerIsAppFrame();
-
   /**
    * Is this a frame loader for a bona fide <iframe mozbrowser>?
    * <xul:browser> is not a mozbrowser, so this is false for that case.
    */
   bool OwnerIsMozBrowserFrame();
 
-  /**
-   * Is this a frame loader for an isolated <iframe mozbrowser>?
-   *
-   * By default, mozbrowser frames are isolated.  Isolation can be disabled by
-   * setting the frame's noisolation attribute.  Disabling isolation is
-   * only allowed if the containing document is chrome.
-   */
-  bool OwnerIsIsolatedMozBrowserFrame();
-
   /**
    * Get our owning element's app manifest URL, or return the empty string if
    * our owning element doesn't have an app manifest URL.
    */
   void GetOwnerAppManifestURL(nsAString& aOut);
 
-  /**
-   * Get the app for our frame.  This is the app whose manifest is returned by
-   * GetOwnerAppManifestURL.
-   */
-  already_AddRefed<mozIApplication> GetOwnApp();
-
-  /**
-   * Get the app which contains this frame.  This is the app associated with
-   * the frame element's principal.
-   */
-  already_AddRefed<mozIApplication> GetContainingApp();
-
   /**
    * If we are an IPC frame, set mRemoteFrame. Otherwise, create and
    * initialize mDocShell.
diff --git a/dom/base/nsGkAtomList.h b/dom/base/nsGkAtomList.h
index de1a4927be..617aea60a7 100644
--- a/dom/base/nsGkAtomList.h
+++ b/dom/base/nsGkAtomList.h
@@ -101,7 +101,6 @@ GK_ATOM(animations, "animations")
 GK_ATOM(anonid, "anonid")
 GK_ATOM(anonlocation, "anonlocation")
 GK_ATOM(any, "any")
-GK_ATOM(mozapp, "mozapp")
 GK_ATOM(applet, "applet")
 GK_ATOM(applyImports, "apply-imports")
 GK_ATOM(applyTemplates, "apply-templates")
@@ -665,7 +664,6 @@ GK_ATOM(nodeSet, "node-set")
 GK_ATOM(noembed, "noembed")
 GK_ATOM(noframes, "noframes")
 GK_ATOM(nohref, "nohref")
-GK_ATOM(noisolation, "noisolation")
 GK_ATOM(nomodule, "nomodule")
 GK_ATOM(nonce, "nonce")
 GK_ATOM(none, "none")
@@ -1003,7 +1001,6 @@ GK_ATOM(panel, "panel")
 GK_ATOM(param, "param")
 GK_ATOM(parameter, "parameter")
 GK_ATOM(parent, "parent")
-GK_ATOM(parentapp, "parentapp")
 GK_ATOM(parentfocused, "parentfocused")
 GK_ATOM(parsetype, "parsetype")
 GK_ATOM(password, "password")
diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index b992c8052a..e100328a8f 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -4490,7 +4490,7 @@ nsGlobalWindow::GetParentOuter()
   }
 
   nsCOMPtr<nsPIDOMWindowOuter> parent;
-  if (mDocShell->GetIsMozBrowserOrApp()) {
+  if (mDocShell->GetIsMozBrowser()) {
     parent = AsOuter();
   } else {
     parent = GetParent();
@@ -4548,7 +4548,7 @@ nsGlobalWindow::GetParent()
   }
 
   nsCOMPtr<nsIDocShell> parent;
-  mDocShell->GetSameTypeParentIgnoreBrowserAndAppBoundaries(getter_AddRefs(parent));
+  mDocShell->GetSameTypeParentIgnoreBrowserBoundaries(getter_AddRefs(parent));
 
   if (parent) {
     nsCOMPtr<nsPIDOMWindowOuter> win = parent->GetWindow();
@@ -4667,9 +4667,9 @@ nsGlobalWindow::GetContentInternal(ErrorResult& aError, bool aUnprivilegedCaller
     return domWindow.forget();
   }
 
-  // If we're contained in <iframe mozbrowser> or <iframe mozapp>, then
-  // GetContent is the same as window.top.
-  if (mDocShell && mDocShell->GetIsInMozBrowserOrApp()) {
+  // If we're contained in <iframe mozbrowser>, then GetContent is the same as
+  // window.top.
+  if (mDocShell && mDocShell->GetIsInMozBrowser()) {
     return GetTopOuter();
   }
 
@@ -7997,7 +7997,7 @@ nsGlobalWindow::ResizeToOuter(int32_t aWidth, int32_t aHeight, ErrorResult& aErr
    * If caller is a browser-element then dispatch a resize event to
    * the embedder.
    */
-  if (mDocShell && mDocShell->GetIsMozBrowserOrApp()) {
+  if (mDocShell && mDocShell->GetIsMozBrowser()) {
     CSSIntSize size(aWidth, aHeight);
     if (!DispatchResizeEvent(size)) {
       // The embedder chose to prevent the default action for this
@@ -8047,7 +8047,7 @@ nsGlobalWindow::ResizeByOuter(int32_t aWidthDif, int32_t aHeightDif,
    * If caller is a browser-element then dispatch a resize event to
    * parent.
    */
-  if (mDocShell && mDocShell->GetIsMozBrowserOrApp()) {
+  if (mDocShell && mDocShell->GetIsMozBrowser()) {
     CSSIntSize size;
     if (NS_FAILED(GetInnerSize(size))) {
       return;
@@ -9018,7 +9018,7 @@ nsGlobalWindow::CloseOuter(bool aTrustedCaller)
   MOZ_RELEASE_ASSERT(IsOuterWindow());
 
   if (!mDocShell || IsInModalState() ||
-      (IsFrame() && !mDocShell->GetIsMozBrowserOrApp())) {
+      (IsFrame() && !mDocShell->GetIsMozBrowser())) {
     // window.close() is called on a frame in a frameset, on a window
     // that's already closed, or on a window for which there's
     // currently a modal dialog open. Ignore such calls.
@@ -9039,14 +9039,13 @@ nsGlobalWindow::CloseOuter(bool aTrustedCaller)
     return;
   }
 
-  // Don't allow scripts from content to close non-app or non-neterror
-  // windows that were not opened by script.
+  // Don't allow scripts from content to close non-neterror windows that
+  // were not opened by script.
   nsAutoString url;
   nsresult rv = mDoc->GetURL(url);
   NS_ENSURE_SUCCESS_VOID(rv);
 
-  if (!mDocShell->GetIsApp() &&
-      !StringBeginsWith(url, NS_LITERAL_STRING("about:neterror")) &&
+  if (!StringBeginsWith(url, NS_LITERAL_STRING("about:neterror")) &&
       !mHadOriginalOpener && !aTrustedCaller) {
     bool allowClose = mAllowScriptsToClose ||
       Preferences::GetBool("dom.allow_scripts_to_close_windows", true);
@@ -9494,7 +9493,7 @@ nsGlobalWindow::GetFrameElementOuter(nsIPrincipal& aSubjectPrincipal)
 {
   MOZ_RELEASE_ASSERT(IsOuterWindow());
 
-  if (!mDocShell || mDocShell->GetIsMozBrowserOrApp()) {
+  if (!mDocShell || mDocShell->GetIsMozBrowser()) {
     return nullptr;
   }
 
@@ -9529,7 +9528,7 @@ nsGlobalWindow::GetRealFrameElementOuter()
   }
 
   nsCOMPtr<nsIDocShell> parent;
-  mDocShell->GetSameTypeParentIgnoreBrowserAndAppBoundaries(getter_AddRefs(parent));
+  mDocShell->GetSameTypeParentIgnoreBrowserBoundaries(getter_AddRefs(parent));
 
   if (!parent || parent == mDocShell) {
     // We're at a chrome boundary, don't expose the chrome iframe
diff --git a/dom/base/nsIFrameLoader.idl b/dom/base/nsIFrameLoader.idl
index d840cdce63..d09dd93421 100644
--- a/dom/base/nsIFrameLoader.idl
+++ b/dom/base/nsIFrameLoader.idl
@@ -5,7 +5,6 @@
 
 #include "nsISupports.idl"
 
-interface mozIApplication;
 interface nsFrameLoader;
 interface nsIDocShell;
 interface nsIURI;
@@ -216,11 +215,10 @@ interface nsIFrameLoader : nsISupports
   [infallible] attribute boolean visible;
 
   /**
-   * Find out whether the owner content really is a mozbrowser or app frame
-   * Especially, a widget frame is regarded as an app frame.  <xul:browser> is
-   * not considered to be a mozbrowser frame.
+   * Find out whether the owner content really is a mozbrowser. <xul:browser>
+   * is not considered to be a mozbrowser frame.
    */
-  readonly attribute boolean ownerIsMozBrowserOrAppFrame;
+  readonly attribute boolean ownerIsMozBrowserFrame;
 
   /**
    * The last known width of the frame. Reading this property will not trigger
@@ -265,12 +263,6 @@ interface nsIFrameLoaderOwner : nsISupports
   [binaryname(FrameLoaderXPCOM)] readonly attribute nsIFrameLoader frameLoader;
   [noscript, notxpcom] alreadyAddRefed_nsFrameLoader GetFrameLoader();
 
-  /**
-   * The principal of parent mozIApplication in case of nested mozbrowser
-   * iframes.
-   */
-  readonly attribute mozIApplication parentApplication;
-
   /**
    * Puts the FrameLoaderOwner in prerendering mode.
    */
diff --git a/dom/base/nsInProcessTabChildGlobal.cpp b/dom/base/nsInProcessTabChildGlobal.cpp
index 8e2b56feca..6adfbdaef0 100644
--- a/dom/base/nsInProcessTabChildGlobal.cpp
+++ b/dom/base/nsInProcessTabChildGlobal.cpp
@@ -88,21 +88,24 @@ nsInProcessTabChildGlobal::DoSendAsyncMessage(JSContext* aCx,
 nsInProcessTabChildGlobal::nsInProcessTabChildGlobal(nsIDocShell* aShell,
                                                      nsIContent* aOwner,
                                                      nsFrameMessageManager* aChrome)
-: mDocShell(aShell), mInitialized(false), mLoadingScript(false),
-  mPreventEventsEscaping(false),
-  mOwner(aOwner), mChromeMessageManager(aChrome)
+: mDocShell(aShell)
+, mInitialized(false)
+, mLoadingScript(false)
+, mPreventEventsEscaping(false)
+, mOwner(aOwner)
+, mChromeMessageManager(aChrome)
 {
   SetIsNotDOMBinding();
   mozilla::HoldJSObjects(this);
 
-  // If owner corresponds to an <iframe mozbrowser> or <iframe mozapp>, we'll
+  // If owner corresponds to an <iframe mozbrowser>, we'll have to tweak our
   // GetEventTargetParent implementation.
   nsCOMPtr<nsIMozBrowserFrame> browserFrame = do_QueryInterface(mOwner);
   if (browserFrame) {
-    mIsBrowserOrAppFrame = browserFrame->GetReallyIsBrowserOrApp();
+    mIsBrowserFrame = browserFrame->GetReallyIsBrowser();
   }
   else {
-    mIsBrowserOrAppFrame = false;
+    mIsBrowserFrame = false;
   }
 }
 
@@ -272,7 +275,7 @@ nsInProcessTabChildGlobal::GetEventTargetParent(EventChainPreVisitor& aVisitor)
     return NS_OK;
   }
 
-  if (mIsBrowserOrAppFrame &&
+  if (mIsBrowserFrame &&
       (!mOwner || !nsContentUtils::IsInChromeDocshell(mOwner->OwnerDoc()))) {
     if (mOwner) {
       if (nsPIDOMWindowInner* innerWindow = mOwner->OwnerDoc()->GetInnerWindow()) {
diff --git a/dom/base/nsInProcessTabChildGlobal.h b/dom/base/nsInProcessTabChildGlobal.h
index 25193d9c8f..3e52472d6a 100644
--- a/dom/base/nsInProcessTabChildGlobal.h
+++ b/dom/base/nsInProcessTabChildGlobal.h
@@ -165,10 +165,9 @@ protected:
   bool mInitialized;
   bool mLoadingScript;
 
-  // Is this the message manager for an in-process <iframe mozbrowser> or
-  // <iframe mozapp>?  This affects where events get sent, so it affects
-  // GetEventTargetParent.
-  bool mIsBrowserOrAppFrame;
+  // Is this the message manager for an in-process <iframe mozbrowser>? This
+  // affects where events get sent, so it affects GetEventTargetParent.
+  bool mIsBrowserFrame;
   bool mPreventEventsEscaping;
 
   // We keep a strong reference to the frameloader after we've started
diff --git a/dom/base/nsJSEnvironment.cpp b/dom/base/nsJSEnvironment.cpp
index 580d6bfba3..c7e17630ab 100644
--- a/dom/base/nsJSEnvironment.cpp
+++ b/dom/base/nsJSEnvironment.cpp
@@ -2265,7 +2265,6 @@ AsmJSCacheOpenEntryForRead(JS::Handle<JSObject*> aGlobal,
 
 static JS::AsmJSCacheResult
 AsmJSCacheOpenEntryForWrite(JS::Handle<JSObject*> aGlobal,
-                            bool aInstalled,
                             const char16_t* aBegin,
                             const char16_t* aEnd,
                             size_t aSize,
@@ -2274,8 +2273,7 @@ AsmJSCacheOpenEntryForWrite(JS::Handle<JSObject*> aGlobal,
 {
   nsIPrincipal* principal =
     nsJSPrincipals::get(JS_GetCompartmentPrincipals(js::GetObjectCompartment(aGlobal)));
-  return asmjscache::OpenEntryForWrite(principal, aInstalled, aBegin, aEnd,
-                                       aSize, aMemory, aHandle);
+  return asmjscache::OpenEntryForWrite(principal, aBegin, aEnd, aSize, aMemory, aHandle);
 }
 
 class AsyncTaskRunnable final : public Runnable
diff --git a/dom/base/nsObjectLoadingContent.cpp b/dom/base/nsObjectLoadingContent.cpp
index e508a22f3e..0f0c9106eb 100644
--- a/dom/base/nsObjectLoadingContent.cpp
+++ b/dom/base/nsObjectLoadingContent.cpp
@@ -1250,17 +1250,6 @@ nsObjectLoadingContent::GetFrameLoader()
   return loader.forget();
 }
 
-NS_IMETHODIMP
-nsObjectLoadingContent::GetParentApplication(mozIApplication** aApplication)
-{
-  if (!aApplication) {
-    return NS_ERROR_FAILURE;
-  }
-
-  *aApplication = nullptr;
-  return NS_OK;
-}
-
 void
 nsObjectLoadingContent::PresetOpenerWindow(mozIDOMWindowProxy* aWindow, mozilla::ErrorResult& aRv)
 {
diff --git a/dom/browser-element/BrowserElementChild.js b/dom/browser-element/BrowserElementChild.js
index 066be66d20..a0921a660c 100644
--- a/dom/browser-element/BrowserElementChild.js
+++ b/dom/browser-element/BrowserElementChild.js
@@ -26,7 +26,7 @@ function parentDocShell(docshell) {
 function isTopBrowserElement(docShell) {
   while (docShell) {
     docShell = parentDocShell(docShell);
-    if (docShell && docShell.isMozBrowserOrApp) {
+    if (docShell && docShell.isMozBrowser) {
       return false;
     }
   }
diff --git a/dom/browser-element/BrowserElementCopyPaste.js b/dom/browser-element/BrowserElementCopyPaste.js
index ffb114f840..029538f81c 100644
--- a/dom/browser-element/BrowserElementCopyPaste.js
+++ b/dom/browser-element/BrowserElementCopyPaste.js
@@ -112,7 +112,7 @@ var CopyPasteAssistent = {
       let targetDocShell = currentWindow
           .QueryInterface(Ci.nsIInterfaceRequestor)
           .getInterface(Ci.nsIWebNavigation);
-      if(targetDocShell.isMozBrowserOrApp) {
+      if(targetDocShell.isMozBrowser) {
         break;
       }
     }
diff --git a/dom/browser-element/BrowserElementParent.cpp b/dom/browser-element/BrowserElementParent.cpp
index 46ceb0a3e9..2575d8b506 100644
--- a/dom/browser-element/BrowserElementParent.cpp
+++ b/dom/browser-element/BrowserElementParent.cpp
@@ -54,23 +54,6 @@ CreateIframe(Element* aOpenerFrameElement, const nsAString& aName, bool aRemote)
 
   popupFrameElement->SetMozbrowser(true);
 
-  // Copy the opener frame's mozapp attribute to the popup frame.
-  if (aOpenerFrameElement->HasAttr(kNameSpaceID_None, nsGkAtoms::mozapp)) {
-    nsAutoString mozapp;
-    aOpenerFrameElement->GetAttr(kNameSpaceID_None, nsGkAtoms::mozapp, mozapp);
-    popupFrameElement->SetAttr(kNameSpaceID_None, nsGkAtoms::mozapp,
-                               mozapp, /* aNotify = */ false);
-  }
-
-  // Copy the opener frame's parentApp attribute to the popup frame.
-  if (aOpenerFrameElement->HasAttr(kNameSpaceID_None, nsGkAtoms::parentapp)) {
-    nsAutoString parentApp;
-    aOpenerFrameElement->GetAttr(kNameSpaceID_None, nsGkAtoms::parentapp,
-                                 parentApp);
-    popupFrameElement->SetAttr(kNameSpaceID_None, nsGkAtoms::parentapp,
-                               parentApp, /* aNotify = */ false);
-  }
-
   // Copy the window name onto the iframe.
   popupFrameElement->SetAttr(kNameSpaceID_None, nsGkAtoms::name,
                              aName, /* aNotify = */ false);
diff --git a/dom/browser-element/mochitest/browserElement_SetInputMethodActive.js b/dom/browser-element/mochitest/browserElement_SetInputMethodActive.js
index 2b94f5cda4..57160137d3 100644
--- a/dom/browser-element/mochitest/browserElement_SetInputMethodActive.js
+++ b/dom/browser-element/mochitest/browserElement_SetInputMethodActive.js
@@ -8,27 +8,6 @@
 SimpleTest.waitForExplicitFinish();
 browserElementTestHelpers.setEnabledPref(true);
 
-// We'll need to get the appId from the current document,
-// it's either SpecialPowers.Ci.nsIScriptSecurityManager.NO_APP_ID when
-// we are not running inside an app (e.g. Firefox Desktop),
-// or the appId of Mochitest app when we are running inside that app
-// (e.g. Emulator).
-var currentAppId = SpecialPowers.wrap(document).nodePrincipal.appId;
-var inApp =
-  currentAppId !== SpecialPowers.Ci.nsIScriptSecurityManager.NO_APP_ID;
-// We will also need the manifest URL and set it on iframes.
-var currentAppManifestURL;
-
-if (inApp) {
-  let appsService = SpecialPowers.Cc["@mozilla.org/AppsService;1"]
-                      .getService(SpecialPowers.Ci.nsIAppsService);
-
-  currentAppManifestURL = appsService.getManifestURLByLocalId(currentAppId);
-};
-
-info('appId=' + currentAppId);
-info('manifestURL=' + currentAppManifestURL);
-
 function setup() {
   let appInfo = SpecialPowers.Cc['@mozilla.org/xre/app-info;1']
                 .getService(SpecialPowers.Ci.nsIXULAppInfo);
@@ -73,9 +52,6 @@ function createFrames() {
    for (let i = 0; i < 2; i++) {
      let frame = gInputMethodFrames[i] = document.createElement('iframe');
      frame.setAttribute('mozbrowser', 'true');
-     if (currentAppManifestURL) {
-       frame.setAttribute('mozapp', currentAppManifestURL);
-     }
      frame.addEventListener('mozbrowserloadend', countLoadend);
      frame.src = 'file_empty.html#' + i;
      document.body.appendChild(frame);
@@ -88,20 +64,10 @@ function setPermissions() {
     allow: true,
     context: {
       url: SimpleTest.getTestFileURL('/file_empty.html'),
-      originAttributes: {
-        appId: currentAppId,
-        inIsolatedMozBrowser: true
-      }
+      originAttributes: {}
     }
   }];
 
-  if (inApp) {
-    // The current document would also need to be given access for IPC to
-    // recognize our permission (why)?
-    permissions.push({
-      type: 'input', allow: true, context: document });
-  }
-
   SpecialPowers.pushPermissions(permissions,
     SimpleTest.waitForFocus.bind(SimpleTest, startTest));
 }
diff --git a/dom/browser-element/mochitest/file_browserElement_AudioChannel_nested.html b/dom/browser-element/mochitest/file_browserElement_AudioChannel_nested.html
index c37a642e2d..de3aab37e9 100644
--- a/dom/browser-element/mochitest/file_browserElement_AudioChannel_nested.html
+++ b/dom/browser-element/mochitest/file_browserElement_AudioChannel_nested.html
@@ -20,7 +20,6 @@
     // set 'remote' to true here will make the the iframe remote in _inproc_
     // test and in-process in _oop_  test.
     iframe.setAttribute('remote', 'true');
-    iframe.setAttribute('mozapp', 'http://example.org/manifest.webapp');
 
     iframe.addEventListener('mozbrowserloadend', function(e) {
       ok("mute" in iframe, "iframe.mute exists");
diff --git a/dom/browser-element/mochitest/priority/mochitest.ini b/dom/browser-element/mochitest/priority/mochitest.ini
index 8118aedd7f..ee442962e8 100644
--- a/dom/browser-element/mochitest/priority/mochitest.ini
+++ b/dom/browser-element/mochitest/priority/mochitest.ini
@@ -13,7 +13,5 @@ support-files =
 
 [test_Simple.html]
 [test_HighPriority.html]
-[test_Preallocated.html]
-disabled = bug 968604, bug 987164
 [test_WebGLContextLost.html]
 disabled = bug 865844
diff --git a/dom/browser-element/mochitest/priority/test_Preallocated.html b/dom/browser-element/mochitest/priority/test_Preallocated.html
deleted file mode 100644
index b2cb0335ee..0000000000
--- a/dom/browser-element/mochitest/priority/test_Preallocated.html
+++ /dev/null
@@ -1,71 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-Test that the preallocated process starts up with priority BACKGROUND.
--->
-<head>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <script type="application/javascript" src="../browserElementTestHelpers.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-
-<script type="application/javascript;version=1.7">
-"use strict";
-
-SimpleTest.waitForExplicitFinish();
-browserElementTestHelpers.setEnabledPref(true);
-browserElementTestHelpers.addPermission();
-browserElementTestHelpers.enableProcessPriorityManager();
-
-var preallocationEnabledPref = null;
-try {
-  preallocationEnabledPref = SpecialPowers.getBoolPref('dom.ipc.processPrelaunch.enabled');
-}
-catch(e) {
-  preallocationEnabledPref = null;
-}
-
-var childID = null;
-
-var cleanedUp = false;
-function cleanUp()
-{
-  if (cleanedUp) {
-    return;
-  }
-
-  cleanedUp = true;
-}
-
-// Even if this test times out, we still want to run cleanUp so as to set the
-// pref back.
-addEventListener('unload', cleanUp);
-
-function runTest()
-{
-  if (preallocationEnabledPref) {
-    ok(false, "dom.ipc.processPrelaunch.enabled must be " +
-              "false for this test to work.");
-    SimpleTest.finish();
-    return;
-  }
-
-  // Ensure that the preallocated process initially gets BACKGROUND priority.
-  // That's it.
-  expectProcessCreated('PREALLOC').then(function() {
-    // We need to set the pref asynchoronously or the preallocated process won't
-    // be shut down.
-    SimpleTest.executeSoon(function(){
-      cleanUp();
-      SimpleTest.finish();
-    });
-  });
-}
-// Setting this pref to true should cause us to prelaunch a process.
-addEventListener('testready', function() {
-  SpecialPowers.pushPrefEnv({'set':[["dom.ipc.processPrelaunch.enabled",true]]},runTest);
-});
-</script>
-</body>
-</html>
diff --git a/dom/cache/Context.cpp b/dom/cache/Context.cpp
index e4c6aed69d..f1b7e50059 100644
--- a/dom/cache/Context.cpp
+++ b/dom/cache/Context.cpp
@@ -259,7 +259,6 @@ Context::QuotaInitRunnable::OpenDirectory()
   QuotaManager::Get()->OpenDirectory(PERSISTENCE_TYPE_DEFAULT,
                                      mQuotaInfo.mGroup,
                                      mQuotaInfo.mOrigin,
-                                     mQuotaInfo.mIsApp,
                                      quota::Client::DOMCACHE,
                                      /* aExclusive */ false,
                                      this);
@@ -376,8 +375,7 @@ Context::QuotaInitRunnable::Run()
       nsresult rv = QuotaManager::GetInfoFromPrincipal(principal,
                                                        &mQuotaInfo.mSuffix,
                                                        &mQuotaInfo.mGroup,
-                                                       &mQuotaInfo.mOrigin,
-                                                       &mQuotaInfo.mIsApp);
+                                                       &mQuotaInfo.mOrigin);
       if (NS_WARN_IF(NS_FAILED(rv))) {
         resolver->Resolve(rv);
         break;
@@ -436,7 +434,6 @@ Context::QuotaInitRunnable::Run()
                                                   mQuotaInfo.mSuffix,
                                                   mQuotaInfo.mGroup,
                                                   mQuotaInfo.mOrigin,
-                                                  mQuotaInfo.mIsApp,
                                                   getter_AddRefs(mQuotaInfo.mDir));
       if (NS_FAILED(rv)) {
         resolver->Resolve(rv);
diff --git a/dom/cache/ManagerId.cpp b/dom/cache/ManagerId.cpp
index b18e0178d4..60a6e7527e 100644
--- a/dom/cache/ManagerId.cpp
+++ b/dom/cache/ManagerId.cpp
@@ -29,8 +29,7 @@ ManagerId::Create(nsIPrincipal* aPrincipal, ManagerId** aManagerIdOut)
   nsresult rv = QuotaManager::GetInfoFromPrincipal(aPrincipal,
                                                    nullptr,   // suffix
                                                    nullptr,   // group
-                                                   &quotaOrigin,
-                                                   nullptr);  // is app
+                                                   &quotaOrigin);
   if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
 
   RefPtr<ManagerId> ref = new ManagerId(aPrincipal, quotaOrigin);
diff --git a/dom/cache/Types.h b/dom/cache/Types.h
index ea10abcd41..7693e18c2a 100644
--- a/dom/cache/Types.h
+++ b/dom/cache/Types.h
@@ -28,12 +28,10 @@ static const CacheId INVALID_CACHE_ID = -1;
 
 struct QuotaInfo
 {
-  QuotaInfo() : mIsApp(false) { }
   nsCOMPtr<nsIFile> mDir;
   nsCString mSuffix;
   nsCString mGroup;
   nsCString mOrigin;
-  bool mIsApp;
 };
 
 } // namespace cache
diff --git a/dom/canvas/WebGLContext.cpp b/dom/canvas/WebGLContext.cpp
index 6c4051e508..b8639a7713 100644
--- a/dom/canvas/WebGLContext.cpp
+++ b/dom/canvas/WebGLContext.cpp
@@ -1824,7 +1824,9 @@ WebGLContext::UpdateContextLossStatus()
 void
 WebGLContext::ForceLoseContext(bool simulateLosing)
 {
+#ifdef DEBUG
     printf_stderr("WebGL(%p)::ForceLoseContext\n", this);
+#endif
     MOZ_ASSERT(!IsContextLost());
     mContextStatus = ContextLostAwaitingEvent;
     mContextLostErrorSet = false;
@@ -1840,7 +1842,9 @@ WebGLContext::ForceLoseContext(bool simulateLosing)
 void
 WebGLContext::ForceRestoreContext()
 {
+#ifdef DEBUG
     printf_stderr("WebGL(%p)::ForceRestoreContext\n", this);
+#endif
     mContextStatus = ContextLostAwaitingRestore;
     mAllowContextRestore = true; // Hey, you did say 'force'.
 
diff --git a/dom/events/EventStateManager.cpp b/dom/events/EventStateManager.cpp
index c6089d5d1c..6213367a68 100644
--- a/dom/events/EventStateManager.cpp
+++ b/dom/events/EventStateManager.cpp
@@ -1279,9 +1279,9 @@ EventStateManager::IsRemoteTarget(nsIContent* target) {
     return true;
   }
 
-  // <frame/iframe mozbrowser/mozapp>
+  // <frame/iframe mozbrowser>
   nsCOMPtr<nsIMozBrowserFrame> browserFrame = do_QueryInterface(target);
-  if (browserFrame && browserFrame->GetReallyIsBrowserOrApp()) {
+  if (browserFrame && browserFrame->GetReallyIsBrowser()) {
     return !!TabParent::GetFrom(target);
   }
 
diff --git a/dom/html/nsBrowserElement.cpp b/dom/html/nsBrowserElement.cpp
index 5b9100fa1d..fb991caba9 100644
--- a/dom/html/nsBrowserElement.cpp
+++ b/dom/html/nsBrowserElement.cpp
@@ -15,11 +15,9 @@
 
 #include "AudioChannelService.h"
 
-#include "mozIApplication.h"
 #include "nsComponentManagerUtils.h"
 #include "nsContentUtils.h"
 #include "nsFrameLoader.h"
-#include "nsIAppsService.h"
 #include "nsIDOMDocument.h"
 #include "nsIDOMDOMRequest.h"
 #include "nsIDOMElement.h"
@@ -44,13 +42,13 @@ nsBrowserElement::IsBrowserElementOrThrow(ErrorResult& aRv)
 void
 nsBrowserElement::InitBrowserElementAPI()
 {
-  bool isMozBrowserOrApp;
+  bool isMozBrowser;
   nsCOMPtr<nsIFrameLoader> frameLoader = GetFrameLoader();
   NS_ENSURE_TRUE_VOID(frameLoader);
-  nsresult rv = frameLoader->GetOwnerIsMozBrowserOrAppFrame(&isMozBrowserOrApp);
+  nsresult rv = frameLoader->GetOwnerIsMozBrowserFrame(&isMozBrowser);
   NS_ENSURE_SUCCESS_VOID(rv);
 
-  if (!isMozBrowserOrApp) {
+  if (!isMozBrowser) {
     return;
   }
 
@@ -495,13 +493,13 @@ nsBrowserElement::GetAllowedAudioChannels(
       return;
     }
 
-    bool isMozBrowserOrApp;
-    aRv = frameLoader->GetOwnerIsMozBrowserOrAppFrame(&isMozBrowserOrApp);
+    bool isMozBrowser;
+    aRv = frameLoader->GetOwnerIsMozBrowserFrame(&isMozBrowser);
     if (NS_WARN_IF(aRv.Failed())) {
       return;
     }
 
-    if (!isMozBrowserOrApp) {
+    if (!isMozBrowser) {
       return;
     }
 
diff --git a/dom/html/nsBrowserElement.h b/dom/html/nsBrowserElement.h
index 9a4c47d28a..f98ce97819 100644
--- a/dom/html/nsBrowserElement.h
+++ b/dom/html/nsBrowserElement.h
@@ -123,7 +123,6 @@ public:
 
 protected:
   NS_IMETHOD_(already_AddRefed<nsFrameLoader>) GetFrameLoader() = 0;
-  NS_IMETHOD GetParentApplication(mozIApplication** aApplication) = 0;
 
   void InitBrowserElementAPI();
   void DestroyBrowserElementFrameScripts();
diff --git a/dom/html/nsGenericHTMLFrameElement.cpp b/dom/html/nsGenericHTMLFrameElement.cpp
index 1d0b6769a6..cc51342b7e 100644
--- a/dom/html/nsGenericHTMLFrameElement.cpp
+++ b/dom/html/nsGenericHTMLFrameElement.cpp
@@ -11,10 +11,8 @@
 #include "mozilla/Preferences.h"
 #include "mozilla/ErrorResult.h"
 #include "GeckoProfiler.h"
-#include "mozIApplication.h"
 #include "nsAttrValueInlines.h"
 #include "nsContentUtils.h"
-#include "nsIAppsService.h"
 #include "nsIDocShell.h"
 #include "nsIDOMDocument.h"
 #include "nsIFrame.h"
@@ -191,31 +189,6 @@ nsGenericHTMLFrameElement::GetFrameLoader()
   return loader.forget();
 }
 
-NS_IMETHODIMP
-nsGenericHTMLFrameElement::GetParentApplication(mozIApplication** aApplication)
-{
-  if (!aApplication) {
-    return NS_ERROR_FAILURE;
-  }
-
-  *aApplication = nullptr;
-
-  nsIPrincipal *principal = NodePrincipal();
-  uint32_t appId = principal->GetAppId();
-
-  nsCOMPtr<nsIAppsService> appsService = do_GetService(APPS_SERVICE_CONTRACTID);
-  if (NS_WARN_IF(!appsService)) {
-    return NS_ERROR_FAILURE;
-  }
-
-  nsresult rv = appsService->GetAppByLocalId(appId, aApplication);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return rv;
-  }
-
-  return NS_OK;
-}
-
 void
 nsGenericHTMLFrameElement::PresetOpenerWindow(mozIDOMWindowProxy* aWindow, ErrorResult& aRv)
 {
@@ -512,144 +485,17 @@ nsGenericHTMLFrameElement::BrowserFramesEnabled()
 }
 
 /**
- * Return true if this frame element really is a mozbrowser or mozapp.  (It
+ * Return true if this frame element really is a mozbrowser.  (It
  * needs to have the right attributes, and its creator must have the right
  * permissions.)
  */
 /* [infallible] */ nsresult
-nsGenericHTMLFrameElement::GetReallyIsBrowserOrApp(bool *aOut)
+nsGenericHTMLFrameElement::GetReallyIsBrowser(bool *aOut)
 {
   *aOut = mReallyIsBrowser;
   return NS_OK;
 }
 
-/* [infallible] */ NS_IMETHODIMP
-nsGenericHTMLFrameElement::GetReallyIsApp(bool *aOut)
-{
-  nsAutoString manifestURL;
-  GetAppManifestURL(manifestURL);
-
-  *aOut = !manifestURL.IsEmpty();
-  return NS_OK;
-}
-
-namespace {
-
-bool NestedEnabled()
-{
-  static bool sMozNestedEnabled = false;
-  static bool sBoolVarCacheInitialized = false;
-
-  if (!sBoolVarCacheInitialized) {
-    sBoolVarCacheInitialized = true;
-    Preferences::AddBoolVarCache(&sMozNestedEnabled,
-                                 "dom.ipc.tabs.nested.enabled");
-  }
-
-  return sMozNestedEnabled;
-}
-
-} // namespace
-
-/* [infallible] */ NS_IMETHODIMP
-nsGenericHTMLFrameElement::GetIsolated(bool *aOut)
-{
-  *aOut = true;
-
-  if (!nsContentUtils::IsSystemPrincipal(NodePrincipal())) {
-    return NS_OK;
-  }
-
-  // Isolation is only disabled if the attribute is present
-  *aOut = !HasAttr(kNameSpaceID_None, nsGkAtoms::noisolation);
-  return NS_OK;
-}
-
-/*
- * Get manifest url of app.
- */
-void nsGenericHTMLFrameElement::GetManifestURL(nsAString& aManifestURL)
-{
-  aManifestURL.Truncate();
-
-  nsAutoString manifestURL;
-  GetAttr(kNameSpaceID_None, nsGkAtoms::mozapp, manifestURL);
-  if (manifestURL.IsEmpty()) {
-    return;
-  }
-
-  // Check permission.
-  nsCOMPtr<nsIPermissionManager> permMgr = services::GetPermissionManager();
-  NS_ENSURE_TRUE_VOID(permMgr);
-  nsIPrincipal *principal = NodePrincipal();
-  const char* aPermissionType = "embed-apps";
-  uint32_t permission = nsIPermissionManager::DENY_ACTION;
-  nsresult rv = permMgr->TestPermissionFromPrincipal(principal,
-                                                     aPermissionType,
-                                                     &permission);
-  NS_ENSURE_SUCCESS_VOID(rv);
-  if (permission != nsIPermissionManager::ALLOW_ACTION) {
-    return;
-  }
-
-  nsCOMPtr<nsIAppsService> appsService = do_GetService(APPS_SERVICE_CONTRACTID);
-  NS_ENSURE_TRUE_VOID(appsService);
-
-  nsCOMPtr<mozIApplication> app;
-  appsService->GetAppByManifestURL(manifestURL, getter_AddRefs(app));
-
-  if (!app) {
-    return;
-  }
-
-  aManifestURL.Assign(manifestURL);
-}
-
-NS_IMETHODIMP
-nsGenericHTMLFrameElement::GetAppManifestURL(nsAString& aOut)
-{
-  aOut.Truncate();
-
-  // At the moment, you can't be an app without being a browser.
-  if (!nsIMozBrowserFrame::GetReallyIsBrowserOrApp()) {
-    return NS_OK;
-  }
-
-  // Only allow content process to embed an app when nested content
-  // process is enabled.
-  if (!XRE_IsParentProcess() &&
-      !(GetBoolAttr(nsGkAtoms::Remote) && NestedEnabled())){
-    NS_WARNING("Can't embed-apps. Embed-apps is restricted to in-proc apps "
-               "or content processes with nested pref enabled, see bug 1097479");
-    return NS_OK;
-  }
-
-  nsAutoString appManifestURL;
-
-  GetManifestURL(appManifestURL);
-
-  bool isApp = !appManifestURL.IsEmpty();
-
-  if (!isApp) {
-    // No valid case to get manifest
-    return NS_OK;
-  }
-
-  if (isApp) {
-    NS_WARNING("Can not simultaneously be mozapp");
-    return NS_OK;
-  }
-
-  nsAutoString manifestURL;
-  if (isApp) {
-    manifestURL.Assign(appManifestURL);
-  }
-
-  aOut.Assign(manifestURL);
-
-  return NS_OK;
-}
-
 NS_IMETHODIMP
 nsGenericHTMLFrameElement::DisallowCreateFrameLoader()
 {
diff --git a/dom/indexedDB/ActorsParent.cpp b/dom/indexedDB/ActorsParent.cpp
index d80b900e76..3ea646d25a 100644
--- a/dom/indexedDB/ActorsParent.cpp
+++ b/dom/indexedDB/ActorsParent.cpp
@@ -74,7 +74,6 @@
 #include "nsHashKeys.h"
 #include "nsNetUtil.h"
 #include "nsISimpleEnumerator.h"
-#include "nsIAppsService.h"
 #include "nsIEventTarget.h"
 #include "nsIFile.h"
 #include "nsIFileURL.h"
@@ -7394,7 +7393,6 @@ protected:
   nsCString mDatabaseId;
   nsString mDatabaseFilePath;
   State mState;
-  bool mIsApp;
   bool mEnforcingQuota;
   const bool mDeleting;
   bool mBlockedDatabaseOpen;
@@ -16904,7 +16902,6 @@ Cursor::RecvContinue(const CursorRequestParams& aParams)
 FileManager::FileManager(PersistenceType aPersistenceType,
                          const nsACString& aGroup,
                          const nsACString& aOrigin,
-                         bool aIsApp,
                          const nsAString& aDatabaseName,
                          bool aEnforcingQuota)
   : mPersistenceType(aPersistenceType)
@@ -16912,7 +16909,6 @@ FileManager::FileManager(PersistenceType aPersistenceType,
   , mOrigin(aOrigin)
   , mDatabaseName(aDatabaseName)
   , mLastFileId(0)
-  , mIsApp(aIsApp)
   , mEnforcingQuota(aEnforcingQuota)
   , mInvalidated(false)
 { }
@@ -18293,7 +18289,7 @@ Maintenance::DirectoryWork()
 
   // The storage directory is structured like this:
   //
-  //   <profile>/storage/<persistence>/<origin>/idb/*.sqlite
+  //   <profile>\storage\<persistence>\<origin>\idb\*.sqlite
   //
   // We have to find all database files that match any persistence type and any
   // origin. We ignore anything out of the ordinary for now.
@@ -18489,7 +18485,6 @@ Maintenance::DirectoryWork()
       nsCString suffix;
       nsCString group;
       nsCString origin;
-      bool isApp;
       nsTArray<nsString> databasePaths;
 
       while (true) {
@@ -18555,8 +18550,7 @@ Maintenance::DirectoryWork()
                                                     &dummyTimeStamp,
                                                     suffix,
                                                     group,
-                                                    origin,
-                                                    &isApp)))) {
+                                                    origin)))) {
             // Not much we can do here...
             continue;
           }
@@ -18582,7 +18576,6 @@ Maintenance::DirectoryWork()
                                                      suffix,
                                                      group,
                                                      origin,
-                                                     isApp,
                                                      getter_AddRefs(directory));
 
         if (NS_WARN_IF(NS_FAILED(rv))) {
@@ -19426,7 +19419,6 @@ UpgradeFileIdsFunction::Init(nsIFile* aFMDirectory,
     new FileManager(PERSISTENCE_TYPE_INVALID,
                     EmptyCString(),
                     EmptyCString(),
-                    false,
                     EmptyString(),
                     false);
 
@@ -20669,7 +20661,6 @@ FactoryOp::FactoryOp(Factory* aFactory,
   , mContentParent(Move(aContentParent))
   , mCommonParams(aCommonParams)
   , mState(State::Initial)
-  , mIsApp(false)
   , mEnforcingQuota(true)
   , mDeleting(aDeleting)
   , mBlockedDatabaseOpen(false)
@@ -21021,13 +21012,11 @@ FactoryOp::CheckPermission(ContentParent* aContentParent,
     }
 
     if (State::Initial == mState) {
-      QuotaManager::GetInfoForChrome(&mSuffix, &mGroup, &mOrigin, &mIsApp);
+      QuotaManager::GetInfoForChrome(&mSuffix, &mGroup, &mOrigin);
 
-      MOZ_ASSERT(!QuotaManager::IsFirstPromptRequired(persistenceType, mOrigin,
-                                                      mIsApp));
+      MOZ_ASSERT(QuotaManager::IsOriginInternal(mOrigin));
 
-      mEnforcingQuota =
-        QuotaManager::IsQuotaEnforced(persistenceType, mOrigin, mIsApp);
+      mEnforcingQuota = false;
     }
 
     *aPermission = PermissionRequestBase::kPermissionAllowed;
@@ -21046,22 +21035,24 @@ FactoryOp::CheckPermission(ContentParent* aContentParent,
   nsCString suffix;
   nsCString group;
   nsCString origin;
-  bool isApp;
   rv = QuotaManager::GetInfoFromPrincipal(principal,
                                           &suffix,
                                           &group,
-                                          &origin,
-                                          &isApp);
+                                          &origin);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
 
   PermissionRequestBase::PermissionValue permission;
 
-  if (QuotaManager::IsFirstPromptRequired(persistenceType, origin, isApp)) {
-    rv = PermissionRequestBase::GetCurrentPermission(principal, &permission);
-    if (NS_WARN_IF(NS_FAILED(rv))) {
-      return rv;
+  if (persistenceType == PERSISTENCE_TYPE_PERSISTENT) {
+    if (QuotaManager::IsOriginInternal(origin)) {
+      permission = PermissionRequestBase::kPermissionAllowed;
+    } else {
+      rv = PermissionRequestBase::GetCurrentPermission(principal, &permission);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
     }
   } else {
     permission = PermissionRequestBase::kPermissionAllowed;
@@ -21072,10 +21063,8 @@ FactoryOp::CheckPermission(ContentParent* aContentParent,
     mSuffix = suffix;
     mGroup = group;
     mOrigin = origin;
-    mIsApp = isApp;
 
-    mEnforcingQuota =
-      QuotaManager::IsQuotaEnforced(persistenceType, mOrigin, mIsApp);
+    mEnforcingQuota = persistenceType != PERSISTENCE_TYPE_PERSISTENT;
   }
 
   *aPermission = permission;
@@ -21232,7 +21221,6 @@ FactoryOp::OpenDirectory()
   quotaManager->OpenDirectory(persistenceType,
                               mGroup,
                               mOrigin,
-                              mIsApp,
                               Client::IDB,
                               /* aExclusive */ false,
                               this);
@@ -21497,7 +21485,6 @@ OpenDatabaseOp::DoDatabaseWork()
                                             mSuffix,
                                             mGroup,
                                             mOrigin,
-                                            mIsApp,
                                             getter_AddRefs(dbDirectory));
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
@@ -21618,7 +21605,6 @@ OpenDatabaseOp::DoDatabaseWork()
     fileManager = new FileManager(persistenceType,
                                   mGroup,
                                   mOrigin,
-                                  mIsApp,
                                   databaseName,
                                   mEnforcingQuota);
 
diff --git a/dom/indexedDB/FileManager.h b/dom/indexedDB/FileManager.h
index 32a1e13303..676f48c6cb 100644
--- a/dom/indexedDB/FileManager.h
+++ b/dom/indexedDB/FileManager.h
@@ -41,7 +41,6 @@ class FileManager final
   // Protected by IndexedDatabaseManager::FileMutex()
   nsDataHashtable<nsUint64HashKey, FileInfo*> mFileInfos;
 
-  const bool mIsApp;
   const bool mEnforcingQuota;
   bool mInvalidated;
 
@@ -65,7 +64,6 @@ public:
   FileManager(PersistenceType aPersistenceType,
               const nsACString& aGroup,
               const nsACString& aOrigin,
-              bool aIsApp,
               const nsAString& aDatabaseName,
               bool aEnforcingQuota);
 
@@ -87,12 +85,6 @@ public:
     return mOrigin;
   }
 
-  bool
-  IsApp() const
-  {
-    return mIsApp;
-  }
-
   const nsAString&
   DatabaseName() const
   {
diff --git a/dom/indexedDB/IDBDatabase.cpp b/dom/indexedDB/IDBDatabase.cpp
index c3f0594957..8e6eb18ee0 100644
--- a/dom/indexedDB/IDBDatabase.cpp
+++ b/dom/indexedDB/IDBDatabase.cpp
@@ -1074,7 +1074,7 @@ IDBDatabase::GetQuotaInfo(nsACString& aOrigin,
       MOZ_CRASH("Is this needed?!");
 
     case PrincipalInfo::TSystemPrincipalInfo:
-      QuotaManager::GetInfoForChrome(nullptr, nullptr, &aOrigin, nullptr);
+      QuotaManager::GetInfoForChrome(nullptr, nullptr, &aOrigin);
       return NS_OK;
 
     case PrincipalInfo::TContentPrincipalInfo: {
@@ -1088,8 +1088,7 @@ IDBDatabase::GetQuotaInfo(nsACString& aOrigin,
       rv = QuotaManager::GetInfoFromPrincipal(principal,
                                               nullptr,
                                               nullptr,
-                                              &aOrigin,
-                                              nullptr);
+                                              &aOrigin);
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return rv;
       }
diff --git a/dom/indexedDB/IndexedDatabaseManager.cpp b/dom/indexedDB/IndexedDatabaseManager.cpp
index 5a6340746f..9d514c599d 100644
--- a/dom/indexedDB/IndexedDatabaseManager.cpp
+++ b/dom/indexedDB/IndexedDatabaseManager.cpp
@@ -1272,7 +1272,6 @@ DeleteFilesRunnable::Open()
   quotaManager->OpenDirectory(mFileManager->Type(),
                               mFileManager->Group(),
                               mFileManager->Origin(),
-                              mFileManager->IsApp(),
                               Client::IDB,
                               /* aExclusive */ false,
                               this);
diff --git a/dom/indexedDB/test/file_app_isolation.html b/dom/indexedDB/test/file_app_isolation.html
deleted file mode 100644
index 0ff74e6897..0000000000
--- a/dom/indexedDB/test/file_app_isolation.html
+++ /dev/null
@@ -1,88 +0,0 @@
-<!DOCTYPE html>
-<html>
-  <body>
-    foobar!
-  </body>
-  <script>
-    var data = [
-      { id: "0", name: "foo" },
-    ];
-
-    var action = window.location.search.substring(1);
-    var finished = false;
-    var created = false; // We use that for 'read-no' action.
-
-    function finish(value) {
-      value ? alert('success') : alert('failure');
-      finished = true;
-    }
-
-    var request = window.indexedDB.open('AppIsolationTest');
-
-    request.onupgradeneeded = function(event) {
-      if (finished) {
-        finish(false);
-        return;
-      }
-
-      switch (action) {
-        case 'read-no':
-          created = true;
-          break;
-        case 'read-yes':
-          finish(false);
-          break;
-        case 'write':
-          created = true;
-
-          var db = event.target.result;
-
-          var objectStore = db.createObjectStore("test", { keyPath: "id" });
-          for (var i in data) {
-            objectStore.add(data[i]);
-          }
-          break;
-      }
-    }
-
-    request.onsuccess = function(event) {
-      if (finished) {
-        finish(false);
-        return;
-      }
-
-      var db = event.target.result;
-
-      // Think about close the db!
-      switch (action) {
-        case 'read-no':
-          db.close();
-
-          if (created) { // That means we have created it.
-            indexedDB.deleteDatabase('AppIsolationTest').onsuccess = function() {
-              finish(true);
-            };
-          } else {
-            finish(false);
-          }
-          break;
-        case 'read-yes':
-          db.transaction("test").objectStore("test").get("0").onsuccess = function(event) {
-            var name = event.target.result.name;
-            db.close();
-
-            indexedDB.deleteDatabase('AppIsolationTest').onsuccess = function() {
-              finish(name == 'foo');
-            };
-          };
-          break;
-        case 'write':
-          db.close();
-
-          // Success only if the db was actually created.
-          finish(created);
-          break;
-      }
-    };
-  </script>
-</html>
diff --git a/dom/indexedDB/test/file_app_isolation.js b/dom/indexedDB/test/file_app_isolation.js
deleted file mode 100644
index d6ed3fab44..0000000000
--- a/dom/indexedDB/test/file_app_isolation.js
+++ /dev/null
@@ -1,161 +0,0 @@
-SimpleTest.waitForExplicitFinish();
-
-var fileTestOnCurrentOrigin = (location.protocol + '//' + location.host + location.pathname)
-                              .replace('test_', 'file_')
-                              .replace('_inproc', '').replace('_oop', '');
-
-var previousPrefs = {
-  mozBrowserFramesEnabled: undefined,
-  oop_by_default: undefined,
-};
-
-try {
-  previousPrefs.mozBrowserFramesEnabled = SpecialPowers.getBoolPref('dom.mozBrowserFramesEnabled');
-} catch(e)
-{
-}
-
-try {
-  previousPrefs.oop_by_default = SpecialPowers.getBoolPref('dom.ipc.browser_frames.oop_by_default');
-} catch(e) {
-}
-
-SpecialPowers.setBoolPref('dom.mozBrowserFramesEnabled', true);
-SpecialPowers.setBoolPref("dom.ipc.browser_frames.oop_by_default", location.pathname.indexOf('_inproc') == -1);
-
-SpecialPowers.addPermission("browser", true, window.document);
-
-var gData = [
-  // APP 1
-  {
-    app: 'http://example.org/manifest.webapp',
-    action: 'read-no',
-    src: fileTestOnCurrentOrigin,
-  },
-  {
-    app: 'http://example.org/manifest.webapp',
-    action: 'write',
-    src: fileTestOnCurrentOrigin,
-  },
-  {
-    app: 'http://example.org/manifest.webapp',
-    action: 'read-yes',
-    src: fileTestOnCurrentOrigin,
-  },
-  // APP 2
-  {
-    app: 'https://example.com/manifest.webapp',
-    action: 'read-no',
-    src: fileTestOnCurrentOrigin,
-  },
-  {
-    app: 'https://example.com/manifest.webapp',
-    action: 'write',
-    src: fileTestOnCurrentOrigin,
-  },
-  {
-    app: 'https://example.com/manifest.webapp',
-    action: 'read-yes',
-    src: fileTestOnCurrentOrigin,
-  },
-  // Browser
-  {
-    browser: true,
-    action: 'read-no',
-    src: fileTestOnCurrentOrigin,
-  },
-  {
-    browser: true,
-    action: 'write',
-    src: fileTestOnCurrentOrigin,
-  },
-  {
-    browser: true,
-    action: 'read-yes',
-    src: fileTestOnCurrentOrigin,
-  },
-];
-
-function runTest() {
-  for (var i in gData) {
-    var iframe = document.createElement('iframe');
-    var data = gData[i];
-
-    if (data.app) {
-      iframe.setAttribute('mozbrowser', '');
-      iframe.setAttribute('mozapp', data.app);
-    } else if (data.browser) {
-      iframe.setAttribute('mozbrowser', '');
-    }
-
-    if (data.app || data.browser) {
-      iframe.addEventListener('mozbrowsershowmodalprompt', function(e) {
-        is(e.detail.message, 'success', 'test number ' + i);
-
-//        document.getElementById('content').removeChild(iframe);
-
-        i++;
-        if (i >= gData.length) {
-          if (previousPrefs.mozBrowserFramesEnabled !== undefined) {
-            SpecialPowers.setBoolPref('dom.mozBrowserFramesEnabled', previousPrefs.mozBrowserFramesEnabled);
-          }
-          if (previousPrefs.oop_by_default !== undefined) {
-            SpecialPowers.setBoolPref("dom.ipc.browser_frames.oop_by_default", previousPrefs.oop_by_default);
-          }
-
-          SpecialPowers.removePermission("browser", window.document);
-
-          indexedDB.deleteDatabase('AppIsolationTest').onsuccess = function() {
-            SimpleTest.finish();
-          };
-        } else {
-          gTestRunner.next();
-        }
-      });
-    }
-
-    iframe.src = data.src + '?' + data.action;
-
-    document.getElementById('content').appendChild(iframe);
-
-    yield undefined;
-  }
-}
-
-var gTestRunner = runTest();
-
-function startTest() {
-  var request = window.indexedDB.open('AppIsolationTest');
-  var created = false;
-
-  request.onupgradeneeded = function(event) {
-    created = true;
-    var db = event.target.result;
-    var data = [
-      { id: "0", name: "foo" },
-    ];
-    var objectStore = db.createObjectStore("test", { keyPath: "id" });
-    for (var i in data) {
-      objectStore.add(data[i]);
-    }
-  }
-
-  request.onsuccess = function(event) {
-    var db = event.target.result;
-    is(created, true, "we should have created the db");
-
-    db.transaction("test").objectStore("test").get("0").onsuccess = function(event) {
-      is(event.target.result.name, 'foo', 'data have been written');
-      db.close();
-
-      gTestRunner.next();
-    };
-  }
-}
-
-// TODO: remove unsetting network.disable.ipc.security as part of bug 820712
-SpecialPowers.pushPrefEnv({
-  "set": [
-    ["network.disable.ipc.security", true],
-  ]
-}, startTest);
diff --git a/dom/indexedDB/test/mochitest.ini b/dom/indexedDB/test/mochitest.ini
index ca65ea8b60..77b66bf057 100644
--- a/dom/indexedDB/test/mochitest.ini
+++ b/dom/indexedDB/test/mochitest.ini
@@ -11,8 +11,6 @@ support-files =
   event_propagation_iframe.html
   exceptions_in_events_iframe.html
   file.js
-  file_app_isolation.html
-  file_app_isolation.js
   helpers.js
   leaving_page_iframe.html
   service_worker.js
@@ -125,12 +123,6 @@ support-files =
 [test_add_put.html]
 [test_add_twice_failure.html]
 [test_advance.html]
-[test_app_isolation_inproc.html]
-# The app isolation tests are only supposed to run in the main process.
-skip-if = e10s
-[test_app_isolation_oop.html]
-# The app isolation tests are only supposed to run in the main process.
-skip-if = e10s
 [test_autoIncrement.html]
 [test_autoIncrement_indexes.html]
 [test_bfcache.html]
diff --git a/dom/indexedDB/test/test_app_isolation_inproc.html b/dom/indexedDB/test/test_app_isolation_inproc.html
deleted file mode 100644
index 571189877f..0000000000
--- a/dom/indexedDB/test/test_app_isolation_inproc.html
+++ /dev/null
@@ -1,21 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=756645
--->
-<head>
-  <title>Test for IndexedDB app isolation (unique process)</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=756645">Mozilla Bug 756645</a>
-<div id="content" style="display: none">
-  
-</div>
-<pre id="test">
-<script type="application/javascript;version=1.7" src="file_app_isolation.js">
-</script>
-</pre>
-</body>
-</html>
diff --git a/dom/indexedDB/test/test_app_isolation_oop.html b/dom/indexedDB/test/test_app_isolation_oop.html
deleted file mode 100644
index 571189877f..0000000000
--- a/dom/indexedDB/test/test_app_isolation_oop.html
+++ /dev/null
@@ -1,21 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=756645
--->
-<head>
-  <title>Test for IndexedDB app isolation (unique process)</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=756645">Mozilla Bug 756645</a>
-<div id="content" style="display: none">
-  
-</div>
-<pre id="test">
-<script type="application/javascript;version=1.7" src="file_app_isolation.js">
-</script>
-</pre>
-</body>
-</html>
diff --git a/dom/inputmethod/Keyboard.jsm b/dom/inputmethod/Keyboard.jsm
index 51506c41fa..13a41a5025 100644
--- a/dom/inputmethod/Keyboard.jsm
+++ b/dom/inputmethod/Keyboard.jsm
@@ -19,10 +19,6 @@ XPCOMUtils.defineLazyServiceGetter(this, "ppmm",
 XPCOMUtils.defineLazyModuleGetter(this, "SystemAppProxy",
                                   "resource://gre/modules/SystemAppProxy.jsm");
 
-XPCOMUtils.defineLazyGetter(this, "appsService", function() {
-  return Cc["@mozilla.org/AppsService;1"].getService(Ci.nsIAppsService);
-});
-
 XPCOMUtils.defineLazyGetter(this, "hardwareKeyHandler", function() {
   return null;
 });
@@ -174,8 +170,8 @@ this.Keyboard = {
         this.formMM = null;
       }
     } else {
-      // Ignore notifications that aren't from a BrowserOrApp
-      if (!frameLoader.ownerIsMozBrowserOrAppFrame) {
+      // Ignore notifications that aren't from a Browser
+      if (!frameLoader.ownerIsMozBrowserFrame) {
         return;
       }
       this.initFormsFrameScript(mm);
@@ -554,24 +550,6 @@ InputRegistryGlue.prototype.addInput = function(msg, mm) {
     mm: mm,
     requestId: msg.data.requestId
   });
-
-  let manifestURL = appsService.getManifestURLByLocalId(msg.data.appId);
-
-  Keyboard.sendToSystem('System:InputRegistry:Add', {
-    id: msgId,
-    manifestURL: manifestURL,
-    inputId: msg.data.inputId,
-    inputManifest: msg.data.inputManifest
-  });
-
-  // XXX: To be removed when content migrate away from mozChromeEvents.
-  SystemAppProxy.dispatchEvent({
-    type: 'inputregistry-add',
-    id: msgId,
-    manifestURL: manifestURL,
-    inputId: msg.data.inputId,
-    inputManifest: msg.data.inputManifest
-  });
 };
 
 InputRegistryGlue.prototype.removeInput = function(msg, mm) {
@@ -580,22 +558,6 @@ InputRegistryGlue.prototype.removeInput = function(msg, mm) {
     mm: mm,
     requestId: msg.data.requestId
   });
-
-  let manifestURL = appsService.getManifestURLByLocalId(msg.data.appId);
-
-  Keyboard.sendToSystem('System:InputRegistry:Remove', {
-    id: msgId,
-    manifestURL: manifestURL,
-    inputId: msg.data.inputId
-  });
-
-  // XXX: To be removed when content migrate away from mozChromeEvents.
-  SystemAppProxy.dispatchEvent({
-    type: 'inputregistry-remove',
-    id: msgId,
-    manifestURL: manifestURL,
-    inputId: msg.data.inputId
-  });
 };
 
 InputRegistryGlue.prototype.returnMessage = function(detail) {
diff --git a/dom/interfaces/apps/moz.build b/dom/interfaces/apps/moz.build
deleted file mode 100644
index 018bda3d80..0000000000
--- a/dom/interfaces/apps/moz.build
+++ /dev/null
@@ -1,13 +0,0 @@
-# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-XPIDL_SOURCES += [
-    'mozIApplication.idl',
-    'mozIApplicationClearPrivateDataParams.idl',
-    'nsIAppsService.idl',
-]
-
-XPIDL_MODULE = 'dom_apps'
-
diff --git a/dom/interfaces/apps/mozIApplication.idl b/dom/interfaces/apps/mozIApplication.idl
deleted file mode 100644
index 3ec506cdba..0000000000
--- a/dom/interfaces/apps/mozIApplication.idl
+++ /dev/null
@@ -1,58 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "domstubs.idl"
-
-interface nsIPrincipal;
-
-/**
- * We expose Gecko-internal helpers related to "web apps" through this
- * sub-interface.
- */
-[scriptable, uuid(e76aa5e0-80b2-404f-bccc-1067828bb6ed)]
-interface mozIApplication: nsISupports
-{
-  /* Return true if this app has |permission|. */
-  boolean hasPermission(in string permission);
-
-  /* Application status as defined in nsIPrincipal. */
-  readonly attribute unsigned short appStatus;
-
-  /* Returns the uuid of the app. */
-  readonly attribute DOMString id;
-
-  /* Returns the origin of the app. */
-  readonly attribute DOMString origin;
-
-  /* Returns the manifest url of the app. */
-  readonly attribute DOMString manifestURL;
-
-  /* Returns the local id of the app. */
-  readonly attribute unsigned long localId;
-
-  /* Returns the base directory for the app */
-  readonly attribute DOMString basePath;
-
-  /* Name copied from the manifest */
-  readonly attribute DOMString name;
-
-  /* CSP copied from the manifest */
-  readonly attribute DOMString csp;
-
-  /* Store ID if the app is installed from a store */
-  readonly attribute DOMString storeID;
-
-  /* Store version if the app is installed from a store */
-  readonly attribute unsigned long storeVersion;
-
-  /* role copied from the manifest */
-  readonly attribute DOMString role;
-
-  /* Returns the kind of the app. */
-  readonly attribute DOMString kind;
-
-  /* Returns the app's principal */
-  readonly attribute nsIPrincipal principal;
-};
diff --git a/dom/interfaces/apps/mozIApplicationClearPrivateDataParams.idl b/dom/interfaces/apps/mozIApplicationClearPrivateDataParams.idl
deleted file mode 100644
index 924fc3f2d3..0000000000
--- a/dom/interfaces/apps/mozIApplicationClearPrivateDataParams.idl
+++ /dev/null
@@ -1,18 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "nsISupports.idl"
-
-[scriptable, uuid(ba0e6c8e-8c03-4b9b-8f9b-4fb14216f56e)]
-interface mozIApplicationClearPrivateDataParams : nsISupports
-{
-  readonly attribute unsigned long appId;
-  readonly attribute boolean browserOnly;
-};
-
-%{C++
-#define TOPIC_WEB_APP_CLEAR_DATA "webapps-clear-data"
-#define TOPIC_CLEAR_ORIGIN_DATA "clear-origin-attributes-data"
-%}
diff --git a/dom/interfaces/apps/nsIAppsService.idl b/dom/interfaces/apps/nsIAppsService.idl
deleted file mode 100644
index 4e91a50eca..0000000000
--- a/dom/interfaces/apps/nsIAppsService.idl
+++ /dev/null
@@ -1,75 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "domstubs.idl"
-
-interface mozIApplication;
-interface nsIURI;
-
-%{C++
-#define APPS_SERVICE_CID { 0x05072afa, 0x92fe, 0x45bf, { 0xae, 0x22, 0x39, 0xb6, 0x9c, 0x11, 0x70, 0x58 } }
-#define APPS_SERVICE_CONTRACTID "@mozilla.org/AppsService;1"
-%}
-
-/*
- * This service allows accessing some DOMApplicationRegistry methods from
- * non-javascript code.
- */
-[scriptable, uuid(711cfab6-7b72-4aa2-a60c-17952ea05661)]
-interface nsIAppsService : nsISupports
-{
-  mozIApplication getAppByManifestURL(in DOMString manifestURL);
-
-  /**
-   * Returns a Promise for the manifest for a given manifestURL.
-   * This is only supported in the parent process: the promise will be rejected
-   * in content processes.
-   */
-  jsval getManifestFor(in DOMString manifestURL);
-
-  /**
-   * Returns the |localId| of the app associated with the |manifestURL| passed
-   * in parameter.
-   * Returns nsIScriptSecurityManager::NO_APP_ID if |manifestURL| isn't a valid
-   * installed manifest URL.
-   */
-  unsigned long getAppLocalIdByManifestURL(in DOMString manifestURL);
-
-  /**
-   * Returns the application associated to this localId.
-   */
-  mozIApplication getAppByLocalId(in unsigned long localId);
-
-  /**
-   * Returns the manifest URL associated to this localId.
-   */
-  DOMString getManifestURLByLocalId(in unsigned long localId);
-
-  /**
-   * Returns the basepath for core apps
-   */
-  DOMString getCoreAppsBasePath();
-
-  /**
-   * Returns the basepath for regular packaged apps
-   */
-  DOMString getWebAppsBasePath();
-
-  /**
-   * Returns true if at least one app is in the registry.
-   */
-  boolean areAnyAppsInstalled();
-
-  jsval getAppInfo(in DOMString appId);
-
-  /**
-   * Returns the localId if the app was installed from a store
-   */
-  DOMString getAppLocalIdByStoreId(in DOMString storeID);
-
-  /**
-   * Returns the scope for app to use with service workers.
-   */
-  DOMString getScopeByLocalId(in unsigned long localId);
-};
diff --git a/dom/interfaces/html/nsIMozBrowserFrame.idl b/dom/interfaces/html/nsIMozBrowserFrame.idl
index 99c6cccf63..175f72e985 100644
--- a/dom/interfaces/html/nsIMozBrowserFrame.idl
+++ b/dom/interfaces/html/nsIMozBrowserFrame.idl
@@ -12,44 +12,13 @@ interface nsITabParent;
 interface nsIMozBrowserFrame : nsIDOMMozBrowserFrame
 {
   /**
-   * Gets whether this frame really is a browser or app frame.
+   * Gets whether this frame really is a browser frame.
    *
    * In order to really be a browser frame, this frame's
    * nsIDOMMozBrowserFrame::mozbrowser attribute must be true, and the frame
    * may have to pass various security checks.
    */
-  [infallible] readonly attribute boolean reallyIsBrowserOrApp;
-
-  /**
-   * Gets whether this frame really is an app frame.
-   *
-   * In order to really be an app frame, this frame must really be a browser
-   * frame (this requirement will go away eventually), and  the frame's mozapp
-   * attribute must point to the manifest of a valid app.
-   */
-  [infallible] readonly attribute boolean reallyIsApp;
-
-  /**
-   * Gets whether this frame is an isolated frame.
-   *
-   * By default, browser frames are isolated, meaning they have a principal
-   * where OriginAttributes.mIsInIsolatedMozBrowser == true.  This isolates
-   * storage and other origin related items from non-browser apps, xul:browsers,
-   * etc.
-   *
-   * Isolation can be disabled by setting the frame's isolated attribute to
-   * false.  Disabling isolation is only allowed if the containing document has
-   * browser permission (or equivalent access).
-   */
-  [infallible] readonly attribute boolean isolated;
-
-  /**
-   * Gets this frame's app manifest URL, if the frame really is an app frame.
-   * Otherwise, returns the empty string.
-   *
-   * This method is guaranteed not to fail.
-   */
-  readonly attribute AString appManifestURL;
+  [infallible] readonly attribute boolean reallyIsBrowser;
 
   /**
    * Normally, a frame tries to create its frame loader when its src is
diff --git a/dom/ipc/ContentBridgeChild.cpp b/dom/ipc/ContentBridgeChild.cpp
index d79ca51d0a..d50f28c1da 100644
--- a/dom/ipc/ContentBridgeChild.cpp
+++ b/dom/ipc/ContentBridgeChild.cpp
@@ -77,7 +77,6 @@ ContentBridgeChild::SendPBrowserConstructor(PBrowserChild* aActor,
                                             const IPCTabContext& aContext,
                                             const uint32_t& aChromeFlags,
                                             const ContentParentId& aCpID,
-                                            const bool& aIsForApp,
                                             const bool& aIsForBrowser)
 {
   return PContentBridgeChild::SendPBrowserConstructor(aActor,
@@ -85,7 +84,6 @@ ContentBridgeChild::SendPBrowserConstructor(PBrowserChild* aActor,
                                                       aContext,
                                                       aChromeFlags,
                                                       aCpID,
-                                                      aIsForApp,
                                                       aIsForBrowser);
 }
 
@@ -130,14 +128,12 @@ ContentBridgeChild::AllocPBrowserChild(const TabId& aTabId,
                                        const IPCTabContext &aContext,
                                        const uint32_t& aChromeFlags,
                                        const ContentParentId& aCpID,
-                                       const bool& aIsForApp,
                                        const bool& aIsForBrowser)
 {
   return nsIContentChild::AllocPBrowserChild(aTabId,
                                              aContext,
                                              aChromeFlags,
                                              aCpID,
-                                             aIsForApp,
                                              aIsForBrowser);
 }
 
@@ -153,7 +149,6 @@ ContentBridgeChild::RecvPBrowserConstructor(PBrowserChild* aActor,
                                             const IPCTabContext& aContext,
                                             const uint32_t& aChromeFlags,
                                             const ContentParentId& aCpID,
-                                            const bool& aIsForApp,
                                             const bool& aIsForBrowser)
 {
   return ContentChild::GetSingleton()->RecvPBrowserConstructor(aActor,
@@ -161,7 +156,6 @@ ContentBridgeChild::RecvPBrowserConstructor(PBrowserChild* aActor,
                                                                aContext,
                                                                aChromeFlags,
                                                                aCpID,
-                                                               aIsForApp,
                                                                aIsForBrowser);
 }
 
diff --git a/dom/ipc/ContentBridgeChild.h b/dom/ipc/ContentBridgeChild.h
index 3b632b806e..c99a134790 100644
--- a/dom/ipc/ContentBridgeChild.h
+++ b/dom/ipc/ContentBridgeChild.h
@@ -42,7 +42,6 @@ public:
                                        const IPCTabContext& aContext,
                                        const uint32_t& aChromeFlags,
                                        const ContentParentId& aCpID,
-                                       const bool& aIsForApp,
                                        const bool& aIsForBrowser) override;
 
   virtual mozilla::ipc::PFileDescriptorSetChild*
@@ -60,7 +59,6 @@ protected:
                                             const IPCTabContext& aContext,
                                             const uint32_t& aChromeFlags,
                                             const ContentParentId& aCpID,
-                                            const bool& aIsForApp,
                                             const bool& aIsForBrowser) override;
   virtual bool DeallocPBrowserChild(PBrowserChild*) override;
   virtual bool RecvPBrowserConstructor(PBrowserChild* aCctor,
@@ -68,7 +66,6 @@ protected:
                                        const IPCTabContext& aContext,
                                        const uint32_t& aChromeFlags,
                                        const ContentParentId& aCpID,
-                                       const bool& aIsForApp,
                                        const bool& aIsForBrowser) override;
 
   virtual mozilla::jsipc::PJavaScriptChild* AllocPJavaScriptChild() override;
diff --git a/dom/ipc/ContentBridgeParent.cpp b/dom/ipc/ContentBridgeParent.cpp
index 973da94ce0..c7e3b1609c 100644
--- a/dom/ipc/ContentBridgeParent.cpp
+++ b/dom/ipc/ContentBridgeParent.cpp
@@ -102,7 +102,6 @@ ContentBridgeParent::SendPBrowserConstructor(PBrowserParent* aActor,
                                              const IPCTabContext& aContext,
                                              const uint32_t& aChromeFlags,
                                              const ContentParentId& aCpID,
-                                             const bool& aIsForApp,
                                              const bool& aIsForBrowser)
 {
   return PContentBridgeParent::SendPBrowserConstructor(aActor,
@@ -110,7 +109,6 @@ ContentBridgeParent::SendPBrowserConstructor(PBrowserParent* aActor,
                                                        aContext,
                                                        aChromeFlags,
                                                        aCpID,
-                                                       aIsForApp,
                                                        aIsForBrowser);
 }
 
@@ -143,14 +141,12 @@ ContentBridgeParent::AllocPBrowserParent(const TabId& aTabId,
                                          const IPCTabContext &aContext,
                                          const uint32_t& aChromeFlags,
                                          const ContentParentId& aCpID,
-                                         const bool& aIsForApp,
                                          const bool& aIsForBrowser)
 {
   return nsIContentParent::AllocPBrowserParent(aTabId,
                                                aContext,
                                                aChromeFlags,
                                                aCpID,
-                                               aIsForApp,
                                                aIsForBrowser);
 }
 
diff --git a/dom/ipc/ContentBridgeParent.h b/dom/ipc/ContentBridgeParent.h
index f79ea453ff..27c7041a2b 100644
--- a/dom/ipc/ContentBridgeParent.h
+++ b/dom/ipc/ContentBridgeParent.h
@@ -42,7 +42,6 @@ public:
                           const IPCTabContext& aContext,
                           const uint32_t& aChromeFlags,
                           const ContentParentId& aCpID,
-                          const bool& aIsForApp,
                           const bool& aIsForBrowser) override;
 
   FORWARD_SHMEM_ALLOCATOR_TO(PContentBridgeParent)
@@ -53,10 +52,6 @@ public:
   {
     return mChildID;
   }
-  virtual bool IsForApp() const override
-  {
-    return mIsForApp;
-  }
   virtual bool IsForBrowser() const override
   {
     return mIsForBrowser;
@@ -75,11 +70,6 @@ protected:
     mChildID = aId;
   }
 
-  void SetIsForApp(bool aIsForApp)
-  {
-    mIsForApp = aIsForApp;
-  }
-
   void SetIsForBrowser(bool aIsForBrowser)
   {
     mIsForBrowser = aIsForBrowser;
@@ -114,7 +104,6 @@ protected:
                       const IPCTabContext &aContext,
                       const uint32_t& aChromeFlags,
                       const ContentParentId& aCpID,
-                      const bool& aIsForApp,
                       const bool& aIsForBrowser) override;
 
   virtual bool DeallocPBrowserParent(PBrowserParent*) override;
@@ -140,7 +129,6 @@ protected: // members
   RefPtr<ContentBridgeParent> mSelfRef;
   Transport* mTransport; // owned
   ContentParentId mChildID;
-  bool mIsForApp;
   bool mIsForBrowser;
 
 private:
diff --git a/dom/ipc/ContentChild.cpp b/dom/ipc/ContentChild.cpp
index 4dd446bb3b..13707cfe5b 100644
--- a/dom/ipc/ContentChild.cpp
+++ b/dom/ipc/ContentChild.cpp
@@ -550,8 +550,7 @@ ContentChild::Init(MessageLoop* aIOLoop,
   SendBackUpXResources(FileDescriptor(xSocketFd));
 #endif
 
-  SendGetProcessAttributes(&mID, &mIsForApp, &mIsForBrowser);
-  InitProcessAttributes();
+  SendGetProcessAttributes(&mID, &mIsForBrowser);
 
 #ifdef NS_PRINTING
   // Force the creation of the nsPrintingProxy so that it's IPC counterpart,
@@ -562,12 +561,6 @@ ContentChild::Init(MessageLoop* aIOLoop,
   return true;
 }
 
-void
-ContentChild::InitProcessAttributes()
-{
-  SetProcessName(NS_LITERAL_STRING("Web Content"), true);
-}
-
 void
 ContentChild::SetProcessName(const nsAString& aName, bool aDontOverride)
 {
@@ -674,7 +667,7 @@ ContentChild::ProvideWindowCommon(TabChild* aTabOpener,
     // We release this ref in DeallocPBrowserChild
     RefPtr<TabChild>(newChild).forget().take(),
     tabId, *ipcContext, aChromeFlags,
-    GetID(), IsForApp(), IsForBrowser());
+    GetID(), IsForBrowser());
 
   nsString name(aName);
   nsAutoCString features(aFeatures);
@@ -1237,15 +1230,6 @@ ContentChild::RecvBidiKeyboardNotify(const bool& aIsLangRTL,
   return true;
 }
 
-static CancelableRunnable* sFirstIdleTask;
-
-static void FirstIdle(void)
-{
-  MOZ_ASSERT(sFirstIdleTask);
-  sFirstIdleTask = nullptr;
-  ContentChild::GetSingleton()->SendFirstIdle();
-}
-
 mozilla::jsipc::PJavaScriptChild *
 ContentChild::AllocPJavaScriptChild()
 {
@@ -1265,14 +1249,12 @@ ContentChild::AllocPBrowserChild(const TabId& aTabId,
                                  const IPCTabContext& aContext,
                                  const uint32_t& aChromeFlags,
                                  const ContentParentId& aCpID,
-                                 const bool& aIsForApp,
                                  const bool& aIsForBrowser)
 {
   return nsIContentChild::AllocPBrowserChild(aTabId,
                                              aContext,
                                              aChromeFlags,
                                              aCpID,
-                                             aIsForApp,
                                              aIsForBrowser);
 }
 
@@ -1282,7 +1264,6 @@ ContentChild::SendPBrowserConstructor(PBrowserChild* aActor,
                                       const IPCTabContext& aContext,
                                       const uint32_t& aChromeFlags,
                                       const ContentParentId& aCpID,
-                                      const bool& aIsForApp,
                                       const bool& aIsForBrowser)
 {
   if (IsShuttingDown()) {
@@ -1294,7 +1275,6 @@ ContentChild::SendPBrowserConstructor(PBrowserChild* aActor,
                                                 aContext,
                                                 aChromeFlags,
                                                 aCpID,
-                                                aIsForApp,
                                                 aIsForBrowser);
 }
 
@@ -1304,7 +1284,6 @@ ContentChild::RecvPBrowserConstructor(PBrowserChild* aActor,
                                       const IPCTabContext& aContext,
                                       const uint32_t& aChromeFlags,
                                       const ContentParentId& aCpID,
-                                      const bool& aIsForApp,
                                       const bool& aIsForBrowser)
 {
   MOZ_ASSERT(!IsShuttingDown());
@@ -1319,23 +1298,6 @@ ContentChild::RecvPBrowserConstructor(PBrowserChild* aActor,
     os->NotifyObservers(tc, "tab-child-created", nullptr);
   }
 
-  static bool hasRunOnce = false;
-  if (!hasRunOnce) {
-      hasRunOnce = true;
-
-    MOZ_ASSERT(!sFirstIdleTask);
-    RefPtr<CancelableRunnable> firstIdleTask = NewCancelableRunnableFunction(FirstIdle);
-    sFirstIdleTask = firstIdleTask;
-    MessageLoop::current()->PostIdleTask(firstIdleTask.forget());
-
-    // Redo InitProcessAttributes() when the app or browser is really
-    // launching so the attributes will be correct.
-    mID = aCpID;
-    mIsForApp = aIsForApp;
-    mIsForBrowser = aIsForBrowser;
-    InitProcessAttributes();
-  }
-
   return true;
 }
 
@@ -1784,9 +1746,6 @@ ContentChild::ActorDestroy(ActorDestroyReason why)
   // keep persistent state.
   ProcessChild::QuickExit();
 #else
-  if (sFirstIdleTask) {
-    sFirstIdleTask->Cancel();
-  }
 
   nsHostObjectProtocolHandler::RemoveDataEntries();
 
@@ -2080,16 +2039,6 @@ ContentChild::RecvCycleCollect()
   return true;
 }
 
-static void
-PreloadSlowThings()
-{
-  // This fetches and creates all the built-in stylesheets.
-  nsLayoutStylesheetCache::Get()->UserContentSheet();
-
-  TabChild::PreloadSlowThings();
-
-}
-
 bool
 ContentChild::RecvAppInfo(const nsCString& version, const nsCString& buildID,
                           const nsCString& name, const nsCString& UAName,
@@ -2105,25 +2054,6 @@ ContentChild::RecvAppInfo(const nsCString& version, const nsCString& buildID,
   return true;
 }
 
-bool
-ContentChild::RecvAppInit()
-{
-  if (!Preferences::GetBool("dom.ipc.processPrelaunch.enabled", false)) {
-    return true;
-  }
-
-  // If we're part of the mozbrowser machinery, go ahead and start
-  // preloading things.  We can only do this for mozbrowser because
-  // PreloadSlowThings() may set the docshell of the first TabChild
-  // inactive, and we can only safely restore it to active from
-  // BrowserElementChild.js.
-  if (mIsForApp || mIsForBrowser) {
-    PreloadSlowThings();
-  }
-
-  return true;
-}
-
 bool
 ContentChild::RecvInitServiceWorkers(const ServiceWorkerConfiguration& aConfig)
 {
diff --git a/dom/ipc/ContentChild.h b/dom/ipc/ContentChild.h
index 0ce61bd6c2..9576af9f47 100644
--- a/dom/ipc/ContentChild.h
+++ b/dom/ipc/ContentChild.h
@@ -91,8 +91,6 @@ public:
             base::ProcessId aParentPid,
             IPC::Channel* aChannel);
 
-  void InitProcessAttributes();
-
   void InitXPCOM();
 
   void InitGraphicsDeviceData();
@@ -173,7 +171,6 @@ public:
                                             const IPCTabContext& aContext,
                                             const uint32_t& aChromeFlags,
                                             const ContentParentId& aCpID,
-                                            const bool& aIsForApp,
                                             const bool& aIsForBrowser) override;
 
   virtual bool DeallocPBrowserChild(PBrowserChild*) override;
@@ -379,8 +376,6 @@ public:
                            const nsCString& name, const nsCString& UAName,
                            const nsCString& ID, const nsCString& vendor) override;
 
-  virtual bool RecvAppInit() override;
-
   virtual bool
   RecvInitServiceWorkers(const ServiceWorkerConfiguration& aConfig) override;
 
@@ -481,7 +476,6 @@ public:
   uint32_t GetMsaaID() const { return mMsaaID; }
 #endif
 
-  bool IsForApp() const { return mIsForApp; }
   bool IsForBrowser() const { return mIsForBrowser; }
 
   virtual PBlobChild*
@@ -502,7 +496,6 @@ public:
                                        const IPCTabContext& context,
                                        const uint32_t& chromeFlags,
                                        const ContentParentId& aCpID,
-                                       const bool& aIsForApp,
                                        const bool& aIsForBrowser) override;
 
   virtual bool RecvPBrowserConstructor(PBrowserChild* aCctor,
@@ -510,7 +503,6 @@ public:
                                        const IPCTabContext& aContext,
                                        const uint32_t& aChromeFlags,
                                        const ContentParentId& aCpID,
-                                       const bool& aIsForApp,
                                        const bool& aIsForBrowser) override;
 
   FORWARD_SHMEM_ALLOCATOR_TO(PContentChild)
@@ -616,7 +608,6 @@ private:
 
   AppInfo mAppInfo;
 
-  bool mIsForApp;
   bool mIsForBrowser;
   bool mCanOverrideProcessName;
   bool mIsAlive;
diff --git a/dom/ipc/ContentParent.cpp b/dom/ipc/ContentParent.cpp
index abb5d3a889..6dab0bbc82 100644
--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -25,7 +25,6 @@
 #include "HandlerServiceParent.h"
 #include "IHistory.h"
 #include "imgIContainer.h"
-#include "mozIApplication.h"
 #if defined(XP_WIN) && defined(ACCESSIBILITY)
 #include "mozilla/a11y/AccessibleWrap.h"
 #endif
@@ -95,7 +94,6 @@
 #include "nsFrameMessageManager.h"
 #include "nsHashPropertyBag.h"
 #include "nsIAlertsService.h"
-#include "nsIAppsService.h"
 #include "nsIClipboard.h"
 #include "nsContentPermissionHelper.h"
 #include "nsICycleCollectorListener.h"
@@ -143,7 +141,6 @@
 #include "nsThreadUtils.h"
 #include "nsToolkitCompsCID.h"
 #include "nsWidgetsCID.h"
-#include "PreallocatedProcessManager.h"
 #include "ProcessPriorityManager.h"
 #include "SandboxHal.h"
 #include "ScreenManagerParent.h"
@@ -456,8 +453,7 @@ ContentParentsMemoryReporter::CollectReports(
   return NS_OK;
 }
 
-nsDataHashtable<nsStringHashKey, ContentParent*>* ContentParent::sAppContentParents;
-nsTArray<ContentParent*>* ContentParent::sNonAppContentParents;
+nsTArray<ContentParent*>* ContentParent::sBrowserContentParents;
 nsTArray<ContentParent*>* ContentParent::sLargeAllocationContentParents;
 nsTArray<ContentParent*>* ContentParent::sPrivateContent;
 StaticAutoPtr<LinkedList<ContentParent> > ContentParent::sContentParents;
@@ -473,11 +469,6 @@ static bool sDisableUnsafeCPOWWarnings = false;
 // The first content child has ID 1, so the chrome process can have ID 0.
 static uint64_t gContentChildID = 1;
 
-// We want the prelaunched process to know that it's for apps, but not
-// actually for any app in particular.  Use a magic manifest URL.
-// Can't be a static constant.
-#define MAGIC_PREALLOCATED_APP_MANIFEST_URL NS_LITERAL_STRING("{{template}}")
-
 static const char* sObserverTopics[] = {
   "xpcom-shutdown",
   "profile-before-change",
@@ -496,77 +487,6 @@ static const char* sObserverTopics[] = {
   "cacheservice:empty-cache",
 };
 
-// PreallocateAppProcess is called by the PreallocatedProcessManager.
-// ContentParent then takes this process back within
-// GetNewOrPreallocatedAppProcess.
-/*static*/ already_AddRefed<ContentParent>
-ContentParent::PreallocateAppProcess()
-{
-  RefPtr<ContentParent> process =
-    new ContentParent(/* app = */ nullptr,
-                      /* aOpener = */ nullptr,
-                      /* isForBrowserElement = */ false,
-                      /* isForPreallocated = */ true);
-
-  if (!process->LaunchSubprocess(PROCESS_PRIORITY_PREALLOC)) {
-    return nullptr;
-  }
-
-  process->Init();
-  return process.forget();
-}
-
-/*static*/ already_AddRefed<ContentParent>
-ContentParent::GetNewOrPreallocatedAppProcess(mozIApplication* aApp,
-                                              ProcessPriority aInitialPriority,
-                                              ContentParent* aOpener,
-                                              /*out*/ bool* aTookPreAllocated)
-{
-  MOZ_ASSERT(aApp);
-  RefPtr<ContentParent> process = PreallocatedProcessManager::Take();
-
-  if (process) {
-    if (!process->SetPriorityAndCheckIsAlive(aInitialPriority)) {
-      // Kill the process just in case it's not actually dead; we don't want
-      // to "leak" this process!
-      process->KillHard("GetNewOrPreallocatedAppProcess");
-    }
-    else {
-      nsAutoString manifestURL;
-      if (NS_FAILED(aApp->GetManifestURL(manifestURL))) {
-        NS_ERROR("Failed to get manifest URL");
-        return nullptr;
-      }
-      process->TransformPreallocatedIntoApp(aOpener, manifestURL);
-      process->ForwardKnownInfo();
-
-      if (aTookPreAllocated) {
-        *aTookPreAllocated = true;
-      }
-      return process.forget();
-    }
-  }
-
-  NS_WARNING("Unable to use pre-allocated app process");
-  process = new ContentParent(aApp,
-                              /* aOpener = */ aOpener,
-                              /* isForBrowserElement = */ false,
-                              /* isForPreallocated = */ false);
-
-  if (!process->LaunchSubprocess(aInitialPriority)) {
-    return nullptr;
-  }
-
-  process->Init();
-  process->ForwardKnownInfo();
-
-  if (aTookPreAllocated) {
-    *aTookPreAllocated = false;
-  }
-
-  return process.forget();
-}
-
 /*static*/ void
 ContentParent::StartUp()
 {
@@ -588,9 +508,6 @@ ContentParent::StartUp()
 
   BackgroundChild::Startup();
 
-  // Try to preallocate a process that we can transform into an app later.
-  PreallocatedProcessManager::AllocateAfterDelay();
-
   sDisableUnsafeCPOWWarnings = PR_GetEnv("DISABLE_UNSAFE_CPOW_WARNINGS");
 }
 
@@ -668,10 +585,10 @@ ContentParent::GetNewOrUsedBrowserProcess(bool aForBrowserElement,
 
     maxContentParents = Preferences::GetInt("dom.ipc.dedicatedProcessCount", 2);
   } else {
-    if (!sNonAppContentParents) {
-      sNonAppContentParents = new nsTArray<ContentParent*>();
+    if (!sBrowserContentParents) {
+      sBrowserContentParents = new nsTArray<ContentParent*>();
     }
-    contentParents = sNonAppContentParents;
+    contentParents = sBrowserContentParents;
 
     maxContentParents = Preferences::GetInt("dom.ipc.processCount", 1);
   }
@@ -687,7 +604,7 @@ ContentParent::GetNewOrUsedBrowserProcess(bool aForBrowserElement,
     uint32_t currIdx = startIdx;
     do {
       RefPtr<ContentParent> p = (*contentParents)[currIdx];
-      NS_ASSERTION(p->IsAlive(), "Non-alive contentparent in sNonAppContntParents?");
+      NS_ASSERTION(p->IsAlive(), "Non-alive contentparent in sBrowserContntParents?");
       if (p->mOpener == aOpener) {
         return p.forget();
       }
@@ -695,24 +612,14 @@ ContentParent::GetNewOrUsedBrowserProcess(bool aForBrowserElement,
     } while (currIdx != startIdx);
   }
 
-  // Try to take and transform the preallocated process into browser.
-  RefPtr<ContentParent> p = PreallocatedProcessManager::Take();
-  if (p) {
-    p->TransformPreallocatedIntoBrowser(aOpener);
-  } else {
-    // Failed in using the preallocated process: fork from the chrome process.
-    p = new ContentParent(/* app = */ nullptr,
-                          aOpener,
-                          aForBrowserElement,
-                          /* isForPreallocated = */ false);
+  RefPtr<ContentParent> p = new ContentParent(aOpener, aForBrowserElement);
 
-    if (!p->LaunchSubprocess(aPriority)) {
-      return nullptr;
-    }
-
-    p->Init();
+  if (!p->LaunchSubprocess(aPriority)) {
+    return nullptr;
   }
 
+  p->Init();
+
   p->mLargeAllocationProcess = aLargeAllocationProcess;
 
   p->ForwardKnownInfo();
@@ -767,18 +674,11 @@ ContentParent::SendAsyncUpdate(nsIWidget* aWidget)
 }
 #endif // defined(XP_WIN)
 
-bool
-ContentParent::PreallocatedProcessReady()
-{
-  return true;
-}
-
 bool
 ContentParent::RecvCreateChildProcess(const IPCTabContext& aContext,
                                       const hal::ProcessPriority& aPriority,
                                       const TabId& aOpenerTabId,
                                       ContentParentId* aCpId,
-                                      bool* aIsForApp,
                                       bool* aIsForBrowser,
                                       TabId* aTabId)
 {
@@ -796,24 +696,16 @@ ContentParent::RecvCreateChildProcess(const IPCTabContext& aContext,
     return false;
   }
 
-  nsCOMPtr<mozIApplication> ownApp = tc.GetTabContext().GetOwnApp();
-  if (ownApp) {
-    cp = GetNewOrPreallocatedAppProcess(ownApp, aPriority, this);
-  }
-  else {
-   cp = GetNewOrUsedBrowserProcess(/* isBrowserElement = */ true,
-                                   aPriority, this);
-  }
+  cp = GetNewOrUsedBrowserProcess(/* isBrowserElement = */ true,
+                                  aPriority, this);
 
   if (!cp) {
     *aCpId = 0;
-    *aIsForApp = false;
     *aIsForBrowser = false;
     return true;
   }
 
   *aCpId = cp->ChildID();
-  *aIsForApp = cp->IsForApp();
   *aIsForBrowser = cp->IsForBrowser();
 
   ContentProcessManager *cpm = ContentProcessManager::GetSingleton();
@@ -944,10 +836,10 @@ ContentParent::RecvFindPlugins(const uint32_t& aPluginEpoch,
 }
 
 /*static*/ TabParent*
-ContentParent::CreateBrowserOrApp(const TabContext& aContext,
-                                  Element* aFrameElement,
-                                  ContentParent* aOpenerContentParent,
-                                  bool aFreshProcess)
+ContentParent::CreateBrowser(const TabContext& aContext,
+                             Element* aFrameElement,
+                             ContentParent* aOpenerContentParent,
+                             bool aFreshProcess)
 {
   PROFILER_LABEL_FUNC(js::ProfileEntry::Category::OTHER);
 
@@ -970,222 +862,74 @@ ContentParent::CreateBrowserOrApp(const TabContext& aContext,
     openerTabId = TabParent::GetTabIdFrom(docShell);
   }
 
-  if (aContext.IsMozBrowserElement() || !aContext.HasOwnApp()) {
-    RefPtr<nsIContentParent> constructorSender;
-    if (isInContentProcess) {
-      MOZ_ASSERT(aContext.IsMozBrowserElement());
-      constructorSender = CreateContentBridgeParent(aContext, initialPriority,
-                                                    openerTabId, &tabId);
-    } else {
-      if (aOpenerContentParent) {
-        constructorSender = aOpenerContentParent;
-      } else {
-        constructorSender =
-          GetNewOrUsedBrowserProcess(aContext.IsMozBrowserElement(),
-                                     initialPriority,
-                                     nullptr,
-                                     aFreshProcess);
-        if (!constructorSender) {
-          return nullptr;
-        }
-      }
-      tabId = AllocateTabId(openerTabId,
-                            aContext.AsIPCTabContext(),
-                            constructorSender->ChildID());
-    }
-    if (constructorSender) {
-      nsCOMPtr<nsIDocShellTreeOwner> treeOwner;
-      docShell->GetTreeOwner(getter_AddRefs(treeOwner));
-      if (!treeOwner) {
-        return nullptr;
-      }
-
-      nsCOMPtr<nsIWebBrowserChrome> wbc = do_GetInterface(treeOwner);
-      if (!wbc) {
-        return nullptr;
-      }
-      uint32_t chromeFlags = 0;
-      wbc->GetChromeFlags(&chromeFlags);
-
-      nsCOMPtr<nsILoadContext> loadContext = do_QueryInterface(docShell);
-      if (loadContext && loadContext->UsePrivateBrowsing()) {
-        chromeFlags |= nsIWebBrowserChrome::CHROME_PRIVATE_WINDOW;
-      }
-      if (docShell->GetAffectPrivateSessionLifetime()) {
-        chromeFlags |= nsIWebBrowserChrome::CHROME_PRIVATE_LIFETIME;
-      }
-
-      if (tabId == 0) {
-        return nullptr;
-      }
-      RefPtr<TabParent> tp(new TabParent(constructorSender, tabId,
-                                         aContext, chromeFlags));
-      tp->SetInitedByParent();
-
-      PBrowserParent* browser =
-      constructorSender->SendPBrowserConstructor(
-        // DeallocPBrowserParent() releases this ref.
-        tp.forget().take(), tabId,
-        aContext.AsIPCTabContext(),
-        chromeFlags,
-        constructorSender->ChildID(),
-        constructorSender->IsForApp(),
-        constructorSender->IsForBrowser());
-
-      if (aFreshProcess) {
-        Unused << browser->SendSetFreshProcess();
-      }
-
-      if (browser) {
-        RefPtr<TabParent> constructedTabParent = TabParent::GetFrom(browser);
-        constructedTabParent->SetOwnerElement(aFrameElement);
-        return constructedTabParent;
-      }
-    }
-    return nullptr;
-  }
-
-  // If we got here, we have an app and we're not a browser element.  ownApp
-  // shouldn't be null, because we otherwise would have gone into the
-  // !HasOwnApp() branch above.
-  RefPtr<nsIContentParent> parent;
-  bool reused = false;
-  bool tookPreallocated = false;
-  nsAutoString manifestURL;
-
+  RefPtr<nsIContentParent> constructorSender;
   if (isInContentProcess) {
-    parent = CreateContentBridgeParent(aContext,
-                                       initialPriority,
-                                       openerTabId,
-                                       &tabId);
-  }
-  else {
-    nsCOMPtr<mozIApplication> ownApp = aContext.GetOwnApp();
-
-    if (!sAppContentParents) {
-      sAppContentParents =
-        new nsDataHashtable<nsStringHashKey, ContentParent*>();
+    MOZ_ASSERT(aContext.IsMozBrowserElement());
+    constructorSender = CreateContentBridgeParent(aContext, initialPriority,
+                                                  openerTabId, &tabId);
+  } else {
+    constructorSender =
+      GetNewOrUsedBrowserProcess(aContext.IsMozBrowserElement(),
+                                 initialPriority, nullptr, aFreshProcess);
+    if (!constructorSender) {
+      return nullptr;
     }
+    tabId = AllocateTabId(openerTabId,
+                          aContext.AsIPCTabContext(),
+                          constructorSender->ChildID());
+  }
 
-    // Each app gets its own ContentParent instance unless it shares it with
-    // a parent app.
-    if (NS_FAILED(ownApp->GetManifestURL(manifestURL))) {
-      NS_ERROR("Failed to get manifest URL");
+  if (constructorSender) {
+    nsCOMPtr<nsIDocShellTreeOwner> treeOwner;
+    docShell->GetTreeOwner(getter_AddRefs(treeOwner));
+    if (!treeOwner) {
       return nullptr;
     }
 
-    RefPtr<ContentParent> p = sAppContentParents->Get(manifestURL);
-
-    if (!p && Preferences::GetBool("dom.ipc.reuse_parent_app")) {
-      nsAutoString parentAppManifestURL;
-      aFrameElement->GetAttr(kNameSpaceID_None,
-                             nsGkAtoms::parentapp, parentAppManifestURL);
-      nsAdoptingString systemAppManifestURL =
-        Preferences::GetString("b2g.system_manifest_url");
-      nsCOMPtr<nsIAppsService> appsService =
-        do_GetService(APPS_SERVICE_CONTRACTID);
-      if (!parentAppManifestURL.IsEmpty() &&
-        !parentAppManifestURL.Equals(systemAppManifestURL) &&
-        appsService) {
-        nsCOMPtr<mozIApplication> parentApp;
-        nsCOMPtr<mozIApplication> app;
-        appsService->GetAppByManifestURL(parentAppManifestURL,
-                                         getter_AddRefs(parentApp));
-        appsService->GetAppByManifestURL(manifestURL,
-                                         getter_AddRefs(app));
-
-        // Only let certified apps re-use the same process.
-        unsigned short parentAppStatus = 0;
-        unsigned short appStatus = 0;
-        if (app &&
-          NS_SUCCEEDED(app->GetAppStatus(&appStatus)) &&
-          appStatus == nsIPrincipal::APP_STATUS_CERTIFIED &&
-          parentApp &&
-          NS_SUCCEEDED(parentApp->GetAppStatus(&parentAppStatus)) &&
-          parentAppStatus == nsIPrincipal::APP_STATUS_CERTIFIED) {
-          // Check if we can re-use the process of the parent app.
-          p = sAppContentParents->Get(parentAppManifestURL);
-        }
-      }
+    nsCOMPtr<nsIWebBrowserChrome> wbc = do_GetInterface(treeOwner);
+    if (!wbc) {
+      return nullptr;
     }
 
-    if (p) {
-      // Check that the process is still alive and set its priority.
-      // Hopefully the process won't die after this point, if this call
-      // succeeds.
-      if (!p->SetPriorityAndCheckIsAlive(initialPriority)) {
-        p = nullptr;
-      }
+    uint32_t chromeFlags = 0;
+    wbc->GetChromeFlags(&chromeFlags);
+
+    nsCOMPtr<nsILoadContext> loadContext = do_QueryInterface(docShell);
+    if (loadContext && loadContext->UsePrivateBrowsing()) {
+      chromeFlags |= nsIWebBrowserChrome::CHROME_PRIVATE_WINDOW;
     }
 
-    reused = !!p;
-    if (!p) {
-      p = GetNewOrPreallocatedAppProcess(ownApp, initialPriority, nullptr,
-                                         &tookPreallocated);
-      MOZ_ASSERT(p);
-      sAppContentParents->Put(manifestURL, p);
-    }
-    tabId = AllocateTabId(openerTabId, aContext.AsIPCTabContext(),
-                          p->ChildID());
-    parent = static_cast<nsIContentParent*>(p);
-  }
-
-  if (!parent || (tabId == 0)) {
-    return nullptr;
-  }
-
-  uint32_t chromeFlags = 0;
-
-  RefPtr<TabParent> tp = new TabParent(parent, tabId, aContext, chromeFlags);
-  tp->SetInitedByParent();
-  PBrowserParent* browser = parent->SendPBrowserConstructor(
-    // DeallocPBrowserParent() releases this ref.
-    RefPtr<TabParent>(tp).forget().take(),
-    tabId,
-    aContext.AsIPCTabContext(),
-    chromeFlags,
-    parent->ChildID(),
-    parent->IsForApp(),
-    parent->IsForBrowser());
-
-  if (aFreshProcess) {
-    Unused << browser->SendSetFreshProcess();
-  }
-
-  if (browser) {
-    RefPtr<TabParent> constructedTabParent = TabParent::GetFrom(browser);
-    constructedTabParent->SetOwnerElement(aFrameElement);
-  }
-
-  if (isInContentProcess) {
-    // Just return directly without the following check in content process.
-    return TabParent::GetFrom(browser);
-  }
-
-  if (!browser) {
-    // We failed to actually start the PBrowser.  This can happen if the
-    // other process has already died.
-    if (!reused) {
-      // Don't leave a broken ContentParent in the hashtable.
-      parent->AsContentParent()->KillHard("CreateBrowserOrApp");
-      sAppContentParents->Remove(manifestURL);
-      parent = nullptr;
+    if (docShell->GetAffectPrivateSessionLifetime()) {
+      chromeFlags |= nsIWebBrowserChrome::CHROME_PRIVATE_LIFETIME;
     }
 
-    // If we took the preallocated process and it was already dead, try
-    // again with a non-preallocated process.  We can be sure this won't
-    // loop forever, because the next time through there will be no
-    // preallocated process to take.
-    if (tookPreallocated) {
-      return ContentParent::CreateBrowserOrApp(aContext, aFrameElement,
-                                               aOpenerContentParent);
+    if (tabId == 0) {
+      return nullptr;
+    }
+    RefPtr<TabParent> tp(new TabParent(constructorSender, tabId,
+                                       aContext, chromeFlags));
+    tp->SetInitedByParent();
+
+    PBrowserParent* browser =
+    constructorSender->SendPBrowserConstructor(
+      // DeallocPBrowserParent() releases this ref.
+      tp.forget().take(), tabId,
+      aContext.AsIPCTabContext(),
+      chromeFlags,
+      constructorSender->ChildID(),
+      constructorSender->IsForBrowser());
+
+    if (aFreshProcess) {
+      Unused << browser->SendSetFreshProcess();
     }
 
-    // Otherwise just give up.
-    return nullptr;
+    if (browser) {
+      RefPtr<TabParent> constructedTabParent = TabParent::GetFrom(browser);
+      constructedTabParent->SetOwnerElement(aFrameElement);
+      return constructedTabParent;
+    }
   }
-
-  return TabParent::GetFrom(browser);
+  return nullptr;
 }
 
 /*static*/ ContentBridgeParent*
@@ -1198,13 +942,11 @@ ContentParent::CreateContentBridgeParent(const TabContext& aContext,
 
   ContentChild* child = ContentChild::GetSingleton();
   ContentParentId cpId;
-  bool isForApp;
   bool isForBrowser;
   if (!child->SendCreateChildProcess(aContext.AsIPCTabContext(),
                                      aPriority,
                                      aOpenerTabId,
                                      &cpId,
-                                     &isForApp,
                                      &isForBrowser,
                                      aTabId)) {
     return nullptr;
@@ -1217,7 +959,6 @@ ContentParent::CreateContentBridgeParent(const TabContext& aContext,
   }
   ContentBridgeParent* parent = child->GetLastBridge();
   parent->SetChildID(cpId);
-  parent->SetIsForApp(isForApp);
   parent->SetIsForBrowser(isForBrowser);
   return parent;
 }
@@ -1336,51 +1077,6 @@ ContentParent::SetPriorityAndCheckIsAlive(ProcessPriority aPriority)
   return true;
 }
 
-// Helper for ContentParent::TransformPreallocatedIntoApp.
-static void
-TryGetNameFromManifestURL(const nsAString& aManifestURL,
-              nsAString& aName)
-{
-  aName.Truncate();
-  if (aManifestURL.IsEmpty() ||
-    aManifestURL == MAGIC_PREALLOCATED_APP_MANIFEST_URL) {
-    return;
-  }
-
-  nsCOMPtr<nsIAppsService> appsService = do_GetService(APPS_SERVICE_CONTRACTID);
-  NS_ENSURE_TRUE_VOID(appsService);
-
-  nsCOMPtr<mozIApplication> app;
-  appsService->GetAppByManifestURL(aManifestURL, getter_AddRefs(app));
-
-  if (!app) {
-    return;
-  }
-
-  app->GetName(aName);
-}
-
-void
-ContentParent::TransformPreallocatedIntoApp(ContentParent* aOpener,
-                                            const nsAString& aAppManifestURL)
-{
-  MOZ_ASSERT(IsPreallocated());
-  mMetamorphosed = true;
-  mOpener = aOpener;
-  mAppManifestURL = aAppManifestURL;
-  TryGetNameFromManifestURL(aAppManifestURL, mAppName);
-}
-
-void
-ContentParent::TransformPreallocatedIntoBrowser(ContentParent* aOpener)
-{
-  // Reset mAppManifestURL, mIsForBrowser and mOSPrivileges for browser.
-  mMetamorphosed = true;
-  mOpener = aOpener;
-  mAppManifestURL.Truncate();
-  mIsForBrowser = true;
-}
-
 void
 ContentParent::ShutDownProcess(ShutDownMethod aMethod)
 {
@@ -1464,29 +1160,19 @@ ContentParent::ShutDownMessageManager()
 void
 ContentParent::MarkAsDead()
 {
-  if (!mAppManifestURL.IsEmpty()) {
-    if (sAppContentParents) {
-      sAppContentParents->Remove(mAppManifestURL);
-      if (!sAppContentParents->Count()) {
-        delete sAppContentParents;
-        sAppContentParents = nullptr;
-      }
-    }
-  } else {
-    if (sNonAppContentParents) {
-      sNonAppContentParents->RemoveElement(this);
-      if (!sNonAppContentParents->Length()) {
-        delete sNonAppContentParents;
-        sNonAppContentParents = nullptr;
-      }
+  if (sBrowserContentParents) {
+    sBrowserContentParents->RemoveElement(this);
+    if (!sBrowserContentParents->Length()) {
+      delete sBrowserContentParents;
+      sBrowserContentParents = nullptr;
     }
+  }
 
-    if (sLargeAllocationContentParents) {
-      sLargeAllocationContentParents->RemoveElement(this);
-      if (!sLargeAllocationContentParents->Length()) {
-        delete sLargeAllocationContentParents;
-        sLargeAllocationContentParents = nullptr;
-      }
+  if (sLargeAllocationContentParents) {
+    sLargeAllocationContentParents->RemoveElement(this);
+    if (!sLargeAllocationContentParents->Length()) {
+      delete sLargeAllocationContentParents;
+      sLargeAllocationContentParents = nullptr;
     }
   }
 
@@ -1789,7 +1475,7 @@ ContentParent::NotifyTabDestroying(const TabId& aTabId,
         return;
     }
 
-    uint32_t numberOfParents = sNonAppContentParents ? sNonAppContentParents->Length() : 0;
+    uint32_t numberOfParents = sBrowserContentParents ? sBrowserContentParents->Length() : 0;
     int32_t processesToKeepAlive = Preferences::GetInt("dom.ipc.keepProcessesAlive", 0);
     if (!cp->mLargeAllocationProcess && static_cast<int32_t>(numberOfParents) <= processesToKeepAlive) {
       return;
@@ -1846,7 +1532,7 @@ ContentParent::NotifyTabDestroyed(const TabId& aTabId,
 
   // We might want to keep alive some content processes for testing, because of performance
   // reasons, but we don't want to alter behavior if the pref is not set.
-  uint32_t numberOfParents = sNonAppContentParents ? sNonAppContentParents->Length() : 0;
+  uint32_t numberOfParents = sBrowserContentParents ? sBrowserContentParents->Length() : 0;
   int32_t processesToKeepAlive = Preferences::GetInt("dom.ipc.keepProcessesAlive", 0);
   bool shouldKeepAliveAny = !mLargeAllocationProcess && processesToKeepAlive > 0;
   bool shouldKeepAliveThis = shouldKeepAliveAny && static_cast<int32_t>(numberOfParents) <= processesToKeepAlive;
@@ -1940,10 +1626,8 @@ ContentParent::LaunchSubprocess(ProcessPriority aInitialPriority /* = PROCESS_PR
   return true;
 }
 
-ContentParent::ContentParent(mozIApplication* aApp,
-                             ContentParent* aOpener,
-                             bool aIsForBrowser,
-                             bool aIsForPreallocated)
+ContentParent::ContentParent(ContentParent* aOpener,
+                             bool aIsForBrowser)
   : nsIContentParent()
   , mOpener(aOpener)
   , mIsForBrowser(aIsForBrowser)
@@ -1951,10 +1635,6 @@ ContentParent::ContentParent(mozIApplication* aApp,
 {
   InitializeMembers();  // Perform common initialization.
 
-  // No more than one of !!aApp, aIsForBrowser, aIsForPreallocated should be
-  // true.
-  MOZ_ASSERT(!!aApp + aIsForBrowser + aIsForPreallocated <= 1);
-
   mMetamorphosed = true;
 
   // Insert ourselves into the global linked list of ContentParent objects.
@@ -1963,13 +1643,6 @@ ContentParent::ContentParent(mozIApplication* aApp,
   }
   sContentParents->insertBack(this);
 
-  if (aApp) {
-    aApp->GetManifestURL(mAppManifestURL);
-    aApp->GetName(mAppName);
-  } else if (aIsForPreallocated) {
-    mAppManifestURL = MAGIC_PREALLOCATED_APP_MANIFEST_URL;
-  }
-
   // From this point on, NS_WARNING, NS_ASSERTION, etc. should print out the
   // PID along with the warning.
   nsDebugImpl::SetMultiprocessMode("Parent");
@@ -1996,19 +1669,10 @@ ContentParent::~ContentParent()
 
   // We should be removed from all these lists in ActorDestroy.
   MOZ_ASSERT(!sPrivateContent || !sPrivateContent->Contains(this));
-  if (mAppManifestURL.IsEmpty()) {
-    MOZ_ASSERT((!sNonAppContentParents ||
-                !sNonAppContentParents->Contains(this)) &&
-               (!sLargeAllocationContentParents ||
-                !sLargeAllocationContentParents->Contains(this)));
-  } else {
-    // In general, we expect sAppContentParents->Get(mAppManifestURL) to be
-    // nullptr.  But it could be that we created another ContentParent for
-    // this app after we did this->ActorDestroy(), so the right check is
-    // that sAppContentParents->Get(mAppManifestURL) != this.
-    MOZ_ASSERT(!sAppContentParents ||
-               sAppContentParents->Get(mAppManifestURL) != this);
-  }
+  MOZ_ASSERT((!sBrowserContentParents ||
+              !sBrowserContentParents->Contains(this)) &&
+             (!sLargeAllocationContentParents ||
+              !sLargeAllocationContentParents->Contains(this)));
 }
 
 void
@@ -2080,11 +1744,6 @@ ContentParent::InitInternal(ProcessPriority aInitialPriority,
     }
   }
 
-  if (gAppData) {
-    // Sending all information to content process.
-    Unused << SendAppInit();
-  }
-
   nsStyleSheetService *sheetService = nsStyleSheetService::GetInstance();
   if (sheetService) {
     // This looks like a lot of work, but in a normal browser session we just
@@ -2144,12 +1803,6 @@ ContentParent::IsAlive() const
   return mIsAlive;
 }
 
-bool
-ContentParent::IsForApp() const
-{
-  return !mAppManifestURL.IsEmpty();
-}
-
 int32_t
 ContentParent::Pid() const
 {
@@ -2390,17 +2043,6 @@ ContentParent::RecvGetShowPasswordSetting(bool* showPassword)
   return true;
 }
 
-bool
-ContentParent::RecvFirstIdle()
-{
-  // When the ContentChild goes idle, it sends us a FirstIdle message
-  // which we use as a good time to prelaunch another process. If we
-  // prelaunch any sooner than this, then we'll be competing with the
-  // child process and slowing it down.
-  PreallocatedProcessManager::AllocateAfterDelay();
-  return true;
-}
-
 bool
 ContentParent::RecvAudioChannelChangeDefVolChannel(const int32_t& aChannel,
                                                    const bool& aHidden)
@@ -2575,10 +2217,9 @@ ContentParent::AllocPProcessHangMonitorParent(Transport* aTransport,
 
 bool
 ContentParent::RecvGetProcessAttributes(ContentParentId* aCpId,
-                                        bool* aIsForApp, bool* aIsForBrowser)
+                                        bool* aIsForBrowser)
 {
   *aCpId = mChildID;
-  *aIsForApp = IsForApp();
   *aIsForBrowser = mIsForBrowser;
 
   return true;
@@ -2687,14 +2328,12 @@ ContentParent::AllocPBrowserParent(const TabId& aTabId,
                                    const IPCTabContext& aContext,
                                    const uint32_t& aChromeFlags,
                                    const ContentParentId& aCpId,
-                                   const bool& aIsForApp,
                                    const bool& aIsForBrowser)
 {
   return nsIContentParent::AllocPBrowserParent(aTabId,
                                                aContext,
                                                aChromeFlags,
                                                aCpId,
-                                               aIsForApp,
                                                aIsForBrowser);
 }
 
@@ -2792,27 +2431,14 @@ ContentParent::KillHard(const char* aReason)
                         otherProcessHandle, /*force=*/true));
 }
 
-bool
-ContentParent::IsPreallocated() const
-{
-  return mAppManifestURL == MAGIC_PREALLOCATED_APP_MANIFEST_URL;
-}
-
 void
 ContentParent::FriendlyName(nsAString& aName, bool aAnonymize)
 {
   aName.Truncate();
-  if (IsPreallocated()) {
-    aName.AssignLiteral("(Preallocated)");
-  } else if (mIsForBrowser) {
+  if (mIsForBrowser) {
     aName.AssignLiteral("Browser");
   } else if (aAnonymize) {
     aName.AssignLiteral("<anonymized-name>");
-  } else if (!mAppName.IsEmpty()) {
-    aName = mAppName;
-  } else if (!mAppManifestURL.IsEmpty()) {
-    aName.AssignLiteral("Unknown app: ");
-    aName.Append(mAppManifestURL);
   } else {
     aName.AssignLiteral("???");
   }
@@ -3649,7 +3275,6 @@ ContentParent::SendPBrowserConstructor(PBrowserParent* aActor,
                                        const IPCTabContext& aContext,
                                        const uint32_t& aChromeFlags,
                                        const ContentParentId& aCpId,
-                                       const bool& aIsForApp,
                                        const bool& aIsForBrowser)
 {
   return PContentParent::SendPBrowserConstructor(aActor,
@@ -3657,7 +3282,6 @@ ContentParent::SendPBrowserConstructor(PBrowserParent* aActor,
                                                  aContext,
                                                  aChromeFlags,
                                                  aCpId,
-                                                 aIsForApp,
                                                  aIsForBrowser);
 }
 
@@ -3775,12 +3399,9 @@ ContentParent::RecvRecordingDeviceEvents(const nsString& aRecordingStatus,
     // recording-device-ipc-events needs to gather more information from content process
     RefPtr<nsHashPropertyBag> props = new nsHashPropertyBag();
     props->SetPropertyAsUint64(NS_LITERAL_STRING("childID"), ChildID());
-    props->SetPropertyAsBool(NS_LITERAL_STRING("isApp"), IsForApp());
     props->SetPropertyAsBool(NS_LITERAL_STRING("isAudio"), aIsAudio);
     props->SetPropertyAsBool(NS_LITERAL_STRING("isVideo"), aIsVideo);
-
-    nsString requestURL = IsForApp() ? AppManifestURL() : aPageURL;
-    props->SetPropertyAsAString(NS_LITERAL_STRING("requestURL"), requestURL);
+    props->SetPropertyAsAString(NS_LITERAL_STRING("requestURL"), aPageURL);
 
     obs->NotifyObservers((nsIPropertyBag2*) props,
                          "recording-device-ipc-events",
@@ -4235,7 +3856,7 @@ ContentParent::RecvCreateWindow(PBrowserParent* aThisTab,
     thisTabParent = TabParent::GetFrom(aThisTab);
   }
 
-  if (NS_WARN_IF(thisTabParent && thisTabParent->IsMozBrowserOrApp())) {
+  if (NS_WARN_IF(thisTabParent && thisTabParent->IsMozBrowser())) {
     return false;
   }
 
diff --git a/dom/ipc/ContentParent.h b/dom/ipc/ContentParent.h
index 561bcf9f68..225aed3d27 100644
--- a/dom/ipc/ContentParent.h
+++ b/dom/ipc/ContentParent.h
@@ -114,8 +114,6 @@ public:
    */
   static void JoinAllSubprocesses();
 
-  static bool PreallocatedProcessReady();
-
   /**
    * Get or create a content process for:
    * 1. browser iframe
@@ -129,21 +127,16 @@ public:
                              ContentParent* aOpener = nullptr,
                              bool aLargeAllocationProcess = false);
 
-  /**
-   * Create a subprocess suitable for use as a preallocated app process.
-   */
-  static already_AddRefed<ContentParent> PreallocateAppProcess();
-
   /**
    * Get or create a content process for the given TabContext.  aFrameElement
    * should be the frame/iframe element with which this process will
    * associated.
    */
   static TabParent*
-  CreateBrowserOrApp(const TabContext& aContext,
-                     Element* aFrameElement,
-                     ContentParent* aOpenerContentParent,
-                     bool aFreshProcess = false);
+  CreateBrowser(const TabContext& aContext,
+                Element* aFrameElement,
+                ContentParent* aOpenerContentParent,
+                bool aFreshProcess = false);
 
   static void GetAll(nsTArray<ContentParent*>& aArray);
 
@@ -231,7 +224,6 @@ public:
                                       const hal::ProcessPriority& aPriority,
                                       const TabId& aOpenerTabId,
                                       ContentParentId* aCpId,
-                                      bool* aIsForApp,
                                       bool* aIsForBrowser,
                                       TabId* aTabId) override;
 
@@ -320,8 +312,6 @@ public:
 
   bool IsAlive() const;
 
-  virtual bool IsForApp() const override;
-
   virtual bool IsForBrowser() const override
   {
     return mIsForBrowser;
@@ -354,10 +344,6 @@ public:
 
   ContentParentId ChildID() const override { return mChildID; }
 
-  const nsString& AppManifestURL() const { return mAppManifestURL; }
-
-  bool IsPreallocated() const;
-
   /**
    * Get a user-friendly name for this ContentParent.  We make no guarantees
    * about this name: It might not be unique, apps can spoof special names,
@@ -543,8 +529,7 @@ protected:
   void OnCompositorUnexpectedShutdown() override;
 
 private:
-  static nsDataHashtable<nsStringHashKey, ContentParent*> *sAppContentParents;
-  static nsTArray<ContentParent*>* sNonAppContentParents;
+  static nsTArray<ContentParent*>* sBrowserContentParents;
   static nsTArray<ContentParent*>* sLargeAllocationContentParents;
   static nsTArray<ContentParent*>* sPrivateContent;
   static StaticAutoPtr<LinkedList<ContentParent> > sContentParents;
@@ -552,15 +537,6 @@ private:
   static void JoinProcessesIOThread(const nsTArray<ContentParent*>* aProcesses,
                                     Monitor* aMonitor, bool* aDone);
 
-  // Take the preallocated process and transform it into a "real" app process,
-  // for the specified manifest URL.  If there is no preallocated process (or
-  // if it's dead), create a new one and set aTookPreAllocated to false.
-  static already_AddRefed<ContentParent>
-  GetNewOrPreallocatedAppProcess(mozIApplication* aApp,
-                                 hal::ProcessPriority aInitialPriority,
-                                 ContentParent* aOpener,
-                                 /*out*/ bool* aTookPreAllocated = nullptr);
-
   static hal::ProcessPriority GetInitialProcessPriority(Element* aFrameElement);
 
   static ContentBridgeParent* CreateContentBridgeParent(const TabContext& aContext,
@@ -576,18 +552,13 @@ private:
       const IPCTabContext& context,
       const uint32_t& chromeFlags,
       const ContentParentId& aCpId,
-      const bool& aIsForApp,
       const bool& aIsForBrowser) override;
   using PContentParent::SendPTestShellConstructor;
 
   FORWARD_SHMEM_ALLOCATOR_TO(PContentParent)
 
-  // No more than one of !!aApp, aIsForBrowser, and aIsForPreallocated may be
-  // true.
-  ContentParent(mozIApplication* aApp,
-                ContentParent* aOpener,
-                bool aIsForBrowser,
-                bool aIsForPreallocated);
+  ContentParent(ContentParent* aOpener,
+                bool aIsForBrowser);
 
   // The common initialization for the constructors.
   void InitializeMembers();
@@ -607,7 +578,7 @@ private:
 
   // Some information could be sent to content very early, it
   // should be send from this function. This function should only be
-  // called after the process has been transformed to app or browser.
+  // called after the process has been transformed to browser.
   void ForwardKnownInfo();
 
   // Set the child process's priority and then check whether the child is
@@ -616,15 +587,6 @@ private:
   // unlikely that the process will be killed after this point.
   bool SetPriorityAndCheckIsAlive(hal::ProcessPriority aPriority);
 
-  // Transform a pre-allocated app process into a "real" app
-  // process, for the specified manifest URL.
-  void TransformPreallocatedIntoApp(ContentParent* aOpener,
-                                    const nsAString& aAppManifestURL);
-
-  // Transform a pre-allocated app process into a browser process. If this
-  // returns false, the child process has died.
-  void TransformPreallocatedIntoBrowser(ContentParent* aOpener);
-
   /**
    * Mark this ContentParent as dead for the purposes of Get*().
    * This method is idempotent.
@@ -683,7 +645,6 @@ private:
                                  ProcessId aOtherProcess) override;
 
   virtual bool RecvGetProcessAttributes(ContentParentId* aCpId,
-                                        bool* aIsForApp,
                                         bool* aIsForBrowser) override;
 
   virtual bool
@@ -708,7 +669,6 @@ private:
                                               const IPCTabContext& aContext,
                                               const uint32_t& aChromeFlags,
                                               const ContentParentId& aCpId,
-                                              const bool& aIsForApp,
                                               const bool& aIsForBrowser) override;
 
   virtual bool DeallocPBrowserParent(PBrowserParent* frame) override;
@@ -907,8 +867,6 @@ private:
 
   virtual bool RecvPrivateDocShellsExist(const bool& aExist) override;
 
-  virtual bool RecvFirstIdle() override;
-
   virtual bool RecvAudioChannelChangeDefVolChannel(const int32_t& aChannel,
                                                    const bool& aHidden) override;
 
@@ -1044,17 +1002,8 @@ private:
   ContentParentId mChildID;
   int32_t mGeolocationWatchID;
 
-  nsString mAppManifestURL;
-
   nsCString mKillHardAnnotation;
 
-  /**
-   * We cache mAppName instead of looking it up using mAppManifestURL when we
-   * need it because it turns out that getting an app from the apps service is
-   * expensive.
-   */
-  nsString mAppName;
-
   // After we initiate shutdown, we also start a timer to ensure
   // that even content processes that are 100% blocked (say from
   // SIGSTOP), are still killed eventually.  This task enforces that
@@ -1070,7 +1019,7 @@ private:
   // through.
   bool mIsAlive;
 
-  // True only the if process is already a browser or app or has
+  // True only the if process is already a browser or has
   // been transformed into one.
   bool mMetamorphosed;
 
diff --git a/dom/ipc/ContentProcessManager.cpp b/dom/ipc/ContentProcessManager.cpp
index 9dbb6a7a2c..959daa484c 100644
--- a/dom/ipc/ContentProcessManager.cpp
+++ b/dom/ipc/ContentProcessManager.cpp
@@ -353,19 +353,5 @@ ContentProcessManager::GetTabParentsByProcessId(const ContentParentId& aChildCpI
   return Move(tabIdList);
 }
 
-uint32_t
-ContentProcessManager::GetAppIdByProcessAndTabId(const ContentParentId& aChildCpId,
-                                                 const TabId& aChildTabId)
-{
-  uint32_t appId = nsIScriptSecurityManager::NO_APP_ID;
-  if (aChildCpId && aChildTabId) {
-    TabContext tabContext;
-    if (GetTabContextByProcessAndTabId(aChildCpId, aChildTabId, &tabContext)) {
-      appId = tabContext.OwnOrContainingAppId();
-    }
-  }
-  return appId;
-}
-
 } // namespace dom
 } // namespace mozilla
diff --git a/dom/ipc/ContentProcessManager.h b/dom/ipc/ContentProcessManager.h
index 8e3bb6d3f8..e48e6e2d65 100644
--- a/dom/ipc/ContentProcessManager.h
+++ b/dom/ipc/ContentProcessManager.h
@@ -142,15 +142,6 @@ public:
   GetTopLevelTabParentByProcessAndTabId(const ContentParentId& aChildCpId,
                                         const TabId& aChildTabId);
 
-  /**
-   * Return appId by given TabId and ContentParentId.
-   * It will return nsIScriptSecurityManager::NO_APP_ID
-   * if the given tab is not an app.
-   */
-  uint32_t
-  GetAppIdByProcessAndTabId(const ContentParentId& aChildCpId,
-                            const TabId& aChildTabId);
-
 private:
   static StaticAutoPtr<ContentProcessManager> sSingleton;
   TabId mUniqueId;
diff --git a/dom/ipc/PContent.ipdl b/dom/ipc/PContent.ipdl
index 3ac02f4b7c..aa25c512e4 100644
--- a/dom/ipc/PContent.ipdl
+++ b/dom/ipc/PContent.ipdl
@@ -264,27 +264,20 @@ both:
     // The child creates the PBrowser as part of
     // TabChild::BrowserFrameProvideWindow (which happens when the child's
     // content calls window.open()), and the parent creates the PBrowser as part
-    // of ContentParent::CreateBrowserOrApp.
+    // of ContentParent::CreateBrowser.
     //
-    // When the parent constructs a PBrowser, the child trusts the app token and
-    // other attributes it receives from the parent.  In that case, the
-    // context should be FrameIPCTabContext.
+    // When the parent constructs a PBrowser, the child trusts the attributes it
+    // receives from the parent.  In that case, the context should be
+    // FrameIPCTabContext.
     //
-    // When the child constructs a PBrowser, the parent doesn't trust the app
-    // token it receives from the child.  In this case, context must have type
-    // PopupIPCTabContext.  The browser created using a PopupIPCTabContext has
-    // the opener PBrowser's app-id and containing-app-id.  The parent checks
-    // that if the opener is a browser element, the context is also for a
-    // browser element.
-    //
-    // This allows the parent to prevent a malicious child from escalating its
-    // privileges by requesting a PBrowser corresponding to a highly-privileged
-    // app; the child can only request privileges for an app which the child has
-    // access to (in the form of a TabChild).
+    // When the child constructs a PBrowser, the parent doesn't trust the
+    // attributes it receives from the child.  In this case, context must have
+    // type PopupIPCTabContext.  The parent checks that if the opener is a
+    // browser element, the context is also for a browser element.
     //
     // Keep the last 3 attributes in sync with GetProcessAttributes!
     async PBrowser(TabId tabId, IPCTabContext context, uint32_t chromeFlags,
-                   ContentParentId cpId, bool isForApp, bool isForBrowser);
+                   ContentParentId cpId, bool isForBrowser);
 
     async PBlob(BlobConstructorParams params);
 
@@ -399,7 +392,6 @@ child:
 
     async AppInfo(nsCString version, nsCString buildID, nsCString name, nsCString UAName,
                   nsCString ID, nsCString vendor);
-    async AppInit();
 
     /**
      * Send ServiceWorkerRegistrationData to child process.
@@ -526,15 +518,13 @@ parent:
      * startup.  (The message is sync to allow the content process to
      * control when it receives the information.)
      *
-     * |id| is a unique ID among all subprocesses.  When |isForApp &&
-     * isForBrowser|, we're loading <browser> for an app.  When
-     * |isForBrowser|, we're loading <browser>.  When |!isForApp &&
-     * !isForBrowser|, we're probably loading <xul:browser remote>.
+     * |id| is a unique ID among all subprocesses. When
+     * |isForBrowser|, we're loading <browser> or <xul:browser remote>.
      *
      * Keep the return values in sync with PBrowser()!
      */
     sync GetProcessAttributes()
-        returns (ContentParentId cpId, bool isForApp, bool isForBrowser);
+        returns (ContentParentId cpId, bool isForBrowser);
     sync GetXPCOMProcessAttributes()
         returns (bool isOffline, bool isConnected, int32_t captivePortalState,
                  bool isLangRTL,
@@ -547,7 +537,7 @@ parent:
     sync CreateChildProcess(IPCTabContext context,
                             ProcessPriority priority,
                             TabId openerTabId)
-        returns (ContentParentId cpId, bool isForApp, bool isForBrowser, TabId tabId);
+        returns (ContentParentId cpId, bool isForBrowser, TabId tabId);
     sync BridgeToChildProcess(ContentParentId cpId);
 
     async CreateGMPService();
@@ -755,9 +745,6 @@ parent:
     // Notify the parent of the presence or absence of private docshells
     async PrivateDocShellsExist(bool aExist);
 
-    // Tell the parent that the child has gone idle for the first time
-    async FirstIdle();
-
     async AudioChannelServiceStatus(bool aActiveTelephonyChannel,
                                     bool aContentOrNormalChannel,
                                     bool aAnyActiveChannel);
diff --git a/dom/ipc/PContentBridge.ipdl b/dom/ipc/PContentBridge.ipdl
index 6be88653d6..72bf4f3adf 100644
--- a/dom/ipc/PContentBridge.ipdl
+++ b/dom/ipc/PContentBridge.ipdl
@@ -54,7 +54,7 @@ both:
     // Both the parent and the child can construct the PBrowser.
     // See the comment in PContent::PBrowser().
     async PBrowser(TabId tabId, IPCTabContext context, uint32_t chromeFlags,
-                   ContentParentId cpId, bool isForApp, bool isForBrowser);
+                   ContentParentId cpId, bool isForBrowser);
 
     async PBlob(BlobConstructorParams params);
 
diff --git a/dom/ipc/PTabContext.ipdlh b/dom/ipc/PTabContext.ipdlh
index 62d6ec0f35..c201b25fe0 100644
--- a/dom/ipc/PTabContext.ipdlh
+++ b/dom/ipc/PTabContext.ipdlh
@@ -38,9 +38,6 @@ struct FrameIPCTabContext
   // The originAttributes dictionary.
   DocShellOriginAttributes originAttributes;
 
-  // The ID of the app containing this app/browser frame, if applicable.
-  uint32_t frameOwnerAppId;
-
   // Whether this is a mozbrowser frame.  <iframe mozbrowser mozapp> and
   // <xul:browser> are not considered to be mozbrowser frames.
   bool isMozBrowserElement;
diff --git a/dom/ipc/PreallocatedProcessManager.cpp b/dom/ipc/PreallocatedProcessManager.cpp
deleted file mode 100644
index c02e0eccf5..0000000000
--- a/dom/ipc/PreallocatedProcessManager.cpp
+++ /dev/null
@@ -1,251 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "mozilla/PreallocatedProcessManager.h"
-#include "mozilla/ClearOnShutdown.h"
-#include "mozilla/Preferences.h"
-#include "mozilla/Unused.h"
-#include "mozilla/dom/ContentParent.h"
-#include "mozilla/dom/ScriptSettings.h"
-#include "nsIPropertyBag2.h"
-#include "ProcessPriorityManager.h"
-#include "nsServiceManagerUtils.h"
-
-// This number is fairly arbitrary ... the intention is to put off
-// launching another app process until the last one has finished
-// loading its content, to reduce CPU/memory/IO contention.
-#define DEFAULT_ALLOCATE_DELAY 1000
-
-using namespace mozilla;
-using namespace mozilla::hal;
-using namespace mozilla::dom;
-
-namespace {
-
-/**
- * This singleton class implements the static methods on
- * PreallocatedProcessManager.
- */
-class PreallocatedProcessManagerImpl final
-  : public nsIObserver
-{
-public:
-  static PreallocatedProcessManagerImpl* Singleton();
-
-  NS_DECL_ISUPPORTS
-  NS_DECL_NSIOBSERVER
-
-  // See comments on PreallocatedProcessManager for these methods.
-  void AllocateAfterDelay();
-  void AllocateOnIdle();
-  void AllocateNow();
-  already_AddRefed<ContentParent> Take();
-
-private:
-  static mozilla::StaticRefPtr<PreallocatedProcessManagerImpl> sSingleton;
-
-  PreallocatedProcessManagerImpl();
-  ~PreallocatedProcessManagerImpl() {}
-  DISALLOW_EVIL_CONSTRUCTORS(PreallocatedProcessManagerImpl);
-
-  void Init();
-
-  void RereadPrefs();
-  void Enable();
-  void Disable();
-
-  void ObserveProcessShutdown(nsISupports* aSubject);
-
-  bool mEnabled;
-  bool mShutdown;
-  RefPtr<ContentParent> mPreallocatedAppProcess;
-};
-
-/* static */ StaticRefPtr<PreallocatedProcessManagerImpl>
-PreallocatedProcessManagerImpl::sSingleton;
-
-/* static */ PreallocatedProcessManagerImpl*
-PreallocatedProcessManagerImpl::Singleton()
-{
-  if (!sSingleton) {
-    sSingleton = new PreallocatedProcessManagerImpl();
-    sSingleton->Init();
-    ClearOnShutdown(&sSingleton);
-  }
-
-  return sSingleton;
-}
-
-NS_IMPL_ISUPPORTS(PreallocatedProcessManagerImpl, nsIObserver)
-
-PreallocatedProcessManagerImpl::PreallocatedProcessManagerImpl()
-  :
-    mEnabled(false)
-  , mShutdown(false)
-{}
-
-void
-PreallocatedProcessManagerImpl::Init()
-{
-  Preferences::AddStrongObserver(this, "dom.ipc.processPrelaunch.enabled");
-  nsCOMPtr<nsIObserverService> os = services::GetObserverService();
-  if (os) {
-    os->AddObserver(this, "ipc:content-shutdown",
-                    /* weakRef = */ false);
-    os->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID,
-                    /* weakRef = */ false);
-  }
-  {
-    RereadPrefs();
-  }
-}
-
-NS_IMETHODIMP
-PreallocatedProcessManagerImpl::Observe(nsISupports* aSubject,
-                                        const char* aTopic,
-                                        const char16_t* aData)
-{
-  if (!strcmp("ipc:content-shutdown", aTopic)) {
-    ObserveProcessShutdown(aSubject);
-  } else if (!strcmp("nsPref:changed", aTopic)) {
-    // The only other observer we registered was for our prefs.
-    RereadPrefs();
-  } else if (!strcmp(NS_XPCOM_SHUTDOWN_OBSERVER_ID, aTopic)) {
-    mShutdown = true;
-  } else {
-    MOZ_ASSERT(false);
-  }
-
-  return NS_OK;
-}
-
-void
-PreallocatedProcessManagerImpl::RereadPrefs()
-{
-  if (Preferences::GetBool("dom.ipc.processPrelaunch.enabled")) {
-    Enable();
-  } else {
-    Disable();
-  }
-}
-
-already_AddRefed<ContentParent>
-PreallocatedProcessManagerImpl::Take()
-{
-  return mPreallocatedAppProcess.forget();
-}
-
-void
-PreallocatedProcessManagerImpl::Enable()
-{
-  if (mEnabled) {
-    return;
-  }
-
-  mEnabled = true;
-  AllocateAfterDelay();
-}
-
-void
-PreallocatedProcessManagerImpl::AllocateAfterDelay()
-{
-  if (!mEnabled || mPreallocatedAppProcess) {
-    return;
-  }
-
-  MessageLoop::current()->PostDelayedTask(
-    NewRunnableMethod(this, &PreallocatedProcessManagerImpl::AllocateOnIdle),
-    Preferences::GetUint("dom.ipc.processPrelaunch.delayMs",
-                         DEFAULT_ALLOCATE_DELAY));
-}
-
-void
-PreallocatedProcessManagerImpl::AllocateOnIdle()
-{
-  if (!mEnabled || mPreallocatedAppProcess) {
-    return;
-  }
-
-  MessageLoop::current()->PostIdleTask(NewRunnableMethod(this, &PreallocatedProcessManagerImpl::AllocateNow));
-}
-
-void
-PreallocatedProcessManagerImpl::AllocateNow()
-{
-  if (!mEnabled || mPreallocatedAppProcess) {
-    return;
-  }
-
-  mPreallocatedAppProcess = ContentParent::PreallocateAppProcess();
-}
-
-void
-PreallocatedProcessManagerImpl::Disable()
-{
-  if (!mEnabled) {
-    return;
-  }
-
-  mEnabled = false;
-
-  if (mPreallocatedAppProcess) {
-    mPreallocatedAppProcess->Close();
-    mPreallocatedAppProcess = nullptr;
-  }
-}
-
-void
-PreallocatedProcessManagerImpl::ObserveProcessShutdown(nsISupports* aSubject)
-{
-  if (!mPreallocatedAppProcess) {
-    return;
-  }
-
-  nsCOMPtr<nsIPropertyBag2> props = do_QueryInterface(aSubject);
-  NS_ENSURE_TRUE_VOID(props);
-
-  uint64_t childID = CONTENT_PROCESS_ID_UNKNOWN;
-  props->GetPropertyAsUint64(NS_LITERAL_STRING("childID"), &childID);
-  NS_ENSURE_TRUE_VOID(childID != CONTENT_PROCESS_ID_UNKNOWN);
-
-  if (childID == mPreallocatedAppProcess->ChildID()) {
-    mPreallocatedAppProcess = nullptr;
-  }
-}
-
-inline PreallocatedProcessManagerImpl* GetPPMImpl()
-{
-  return PreallocatedProcessManagerImpl::Singleton();
-}
-
-} // namespace
-
-namespace mozilla {
-
-/* static */ void
-PreallocatedProcessManager::AllocateAfterDelay()
-{
-  GetPPMImpl()->AllocateAfterDelay();
-}
-
-/* static */ void
-PreallocatedProcessManager::AllocateOnIdle()
-{
-  GetPPMImpl()->AllocateOnIdle();
-}
-
-/* static */ void
-PreallocatedProcessManager::AllocateNow()
-{
-  GetPPMImpl()->AllocateNow();
-}
-
-/* static */ already_AddRefed<ContentParent>
-PreallocatedProcessManager::Take()
-{
-  return GetPPMImpl()->Take();
-}
-
-} // namespace mozilla
diff --git a/dom/ipc/PreallocatedProcessManager.h b/dom/ipc/PreallocatedProcessManager.h
deleted file mode 100644
index 5945616272..0000000000
--- a/dom/ipc/PreallocatedProcessManager.h
+++ /dev/null
@@ -1,87 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef mozilla_PreallocatedProcessManager_h
-#define mozilla_PreallocatedProcessManager_h
-
-#include "base/basictypes.h"
-#include "nsCOMPtr.h"
-#include "nsIObserver.h"
-
-namespace mozilla {
-namespace dom {
-class ContentParent;
-} // namespace dom
-
-/**
- * This class manages a ContentParent that it starts up ahead of any particular
- * need.  You can then call Take() to get this process and use it.  Since we
- * already started it up, it should be ready for use faster than if you'd
- * created the process when you needed it.
- *
- * This class watches the dom.ipc.processPrelaunch.enabled pref.  If it changes
- * from false to true, it preallocates a process.  If it changes from true to
- * false, it kills the preallocated process, if any.
- *
- * We don't expect this pref to flip between true and false in production, but
- * flipping the pref is important for tests.
- *
- * The static methods here are implemented by forwarding calls on to a
- * PreallocatedProcessManagerImpl singleton class, so if you add a new static
- * method here, you'll need to write a corresponding public method on the
- * singleton.
- */
-class PreallocatedProcessManager final
-{
-  typedef mozilla::dom::ContentParent ContentParent;
-
-public:
-  /**
-   * Create a process after a delay.  We wait for a period of time (specified
-   * by the dom.ipc.processPrelaunch.delayMs pref), then wait for this process
-   * to go idle, then allocate the new process.
-   *
-   * If the dom.ipc.processPrelaunch.enabled pref is false, or if we already
-   * have a preallocated process, this function does nothing.
-   */
-  static void AllocateAfterDelay();
-
-  /**
-   * Create a process once this process goes idle.
-   *
-   * If the dom.ipc.processPrelaunch.enabled pref is false, or if we already
-   * have a preallocated process, this function does nothing.
-   */
-  static void AllocateOnIdle();
-
-  /**
-   * Create a process right now.
-   *
-   * If the dom.ipc.processPrelaunch.enabled pref is false, or if we already
-   * have a preallocated process, this function does nothing.
-   */
-  static void AllocateNow();
-
-  /**
-   * Take the preallocated process, if we have one.  If we don't have one, this
-   * returns null.
-   *
-   * If you call Take() twice in a row, the second call is guaranteed to return
-   * null.
-   *
-   * After you Take() the preallocated process, you need to call one of the
-   * Allocate* functions (or change the dom.ipc.processPrelaunch pref from
-   * false to true) before we'll create a new process.
-   */
-  static already_AddRefed<ContentParent> Take();
-
-private:
-  PreallocatedProcessManager();
-  DISALLOW_EVIL_CONSTRUCTORS(PreallocatedProcessManager);
-};
-
-} // namespace mozilla
-
-#endif // defined mozilla_PreallocatedProcessManager_h
diff --git a/dom/ipc/ProcessPriorityManager.cpp b/dom/ipc/ProcessPriorityManager.cpp
index 51c42f7a52..07548f8ee2 100644
--- a/dom/ipc/ProcessPriorityManager.cpp
+++ b/dom/ipc/ProcessPriorityManager.cpp
@@ -300,7 +300,6 @@ public:
 
   int32_t Pid() const;
   uint64_t ChildID() const;
-  bool IsPreallocated() const;
 
   /**
    * Used in logging, this method returns the ContentParent's name followed by
@@ -617,15 +616,12 @@ ProcessPriorityManagerImpl::NotifyProcessPriorityChanged(
   ProcessPriority aOldPriority)
 {
   ProcessPriority newPriority = aParticularManager->CurrentPriority();
-  bool isPreallocated = aParticularManager->IsPreallocated();
 
   if (newPriority == PROCESS_PRIORITY_BACKGROUND &&
-      aOldPriority != PROCESS_PRIORITY_BACKGROUND &&
-      !isPreallocated) {
+      aOldPriority != PROCESS_PRIORITY_BACKGROUND) {
     mBackgroundLRUPool.Add(aParticularManager);
   } else if (newPriority != PROCESS_PRIORITY_BACKGROUND &&
-      aOldPriority == PROCESS_PRIORITY_BACKGROUND &&
-      !isPreallocated) {
+      aOldPriority == PROCESS_PRIORITY_BACKGROUND) {
     mBackgroundLRUPool.Remove(aParticularManager);
   }
 
@@ -808,12 +804,6 @@ ParticularProcessPriorityManager::Pid() const
   return mContentParent ? mContentParent->Pid() : -1;
 }
 
-bool
-ParticularProcessPriorityManager::IsPreallocated() const
-{
-  return mContentParent ? mContentParent->IsPreallocated() : false;
-}
-
 const nsAutoCString&
 ParticularProcessPriorityManager::NameWithComma()
 {
@@ -860,10 +850,10 @@ ParticularProcessPriorityManager::OnRemoteBrowserFrameShown(nsISupports* aSubjec
     return;
   }
 
-  // Ignore notifications that aren't from a BrowserOrApp
-  bool isMozBrowserOrApp;
-  fl->GetOwnerIsMozBrowserOrAppFrame(&isMozBrowserOrApp);
-  if (isMozBrowserOrApp) {
+  // Ignore notifications that aren't from a Browser
+  bool isMozBrowser;
+  fl->GetOwnerIsMozBrowserFrame(&isMozBrowser);
+  if (isMozBrowser) {
     ResetPriority();
   }
 
diff --git a/dom/ipc/TabChild.cpp b/dom/ipc/TabChild.cpp
index caae91fa54..ed183eb1b2 100644
--- a/dom/ipc/TabChild.cpp
+++ b/dom/ipc/TabChild.cpp
@@ -44,7 +44,6 @@
 #include "mozilla/TextEvents.h"
 #include "mozilla/TouchEvents.h"
 #include "mozilla/Unused.h"
-#include "mozIApplication.h"
 #include "nsContentUtils.h"
 #include "nsCSSFrameConstructor.h"
 #include "nsDocShell.h"
@@ -98,7 +97,6 @@
 #include "nsColorPickerProxy.h"
 #include "nsContentPermissionHelper.h"
 #include "nsPresShell.h"
-#include "nsIAppsService.h"
 #include "nsNetUtil.h"
 #include "nsIPermissionManager.h"
 #include "nsIURILoader.h"
@@ -319,8 +317,6 @@ private:
 };
 
 namespace {
-StaticRefPtr<TabChild> sPreallocatedTab;
-
 std::map<TabId, RefPtr<TabChild>>&
 NestedTabChildMap()
 {
@@ -341,91 +337,13 @@ TabChild::FindTabChild(const TabId& aTabId)
   return tabChild.forget();
 }
 
-static void
-PreloadSlowThingsPostFork(void* aUnused)
-{
-    nsCOMPtr<nsIObserverService> observerService =
-      mozilla::services::GetObserverService();
-    observerService->NotifyObservers(nullptr, "preload-postfork", nullptr);
-
-    MOZ_ASSERT(sPreallocatedTab);
-    // Initialize initial reflow of the PresShell has to happen after fork
-    // because about:blank content viewer is created in the above observer
-    // notification.
-    nsCOMPtr<nsIDocShell> docShell =
-      do_GetInterface(sPreallocatedTab->WebNavigation());
-    if (nsIPresShell* presShell = docShell->GetPresShell()) {
-        // Initialize and do an initial reflow of the about:blank
-        // PresShell to let it preload some things for us.
-        presShell->Initialize(0, 0);
-        nsIDocument* doc = presShell->GetDocument();
-        doc->FlushPendingNotifications(Flush_Layout);
-        // ... but after it's done, make sure it doesn't do any more
-        // work.
-        presShell->MakeZombie();
-    }
-
-}
-
-static bool sPreloaded = false;
-
-/*static*/ void
-TabChild::PreloadSlowThings()
-{
-    if (sPreloaded) {
-        // If we are alredy initialized in Nuwa, don't redo preloading.
-        return;
-    }
-    sPreloaded = true;
-
-    // Pass nullptr to aManager since at this point the TabChild is
-    // not connected to any manager. Any attempt to use the TabChild
-    // in IPC will crash.
-    RefPtr<TabChild> tab(new TabChild(nullptr,
-                                        TabId(0),
-                                        TabContext(), /* chromeFlags */ 0));
-    if (!NS_SUCCEEDED(tab->Init()) ||
-        !tab->InitTabChildGlobal(DONT_LOAD_SCRIPTS)) {
-        return;
-    }
-
-    // Just load and compile these scripts, but don't run them.
-    tab->TryCacheLoadAndCompileScript(BROWSER_ELEMENT_CHILD_SCRIPT, true);
-    // Load, compile, and run these scripts.
-    tab->RecvLoadRemoteScript(
-        NS_LITERAL_STRING("chrome://global/content/preload.js"),
-        true);
-
-    sPreallocatedTab = tab;
-    ClearOnShutdown(&sPreallocatedTab);
-
-    PreloadSlowThingsPostFork(nullptr);
-}
-
 /*static*/ already_AddRefed<TabChild>
 TabChild::Create(nsIContentChild* aManager,
                  const TabId& aTabId,
                  const TabContext &aContext,
                  uint32_t aChromeFlags)
 {
-    if (sPreallocatedTab &&
-        sPreallocatedTab->mChromeFlags == aChromeFlags &&
-        aContext.IsMozBrowserOrApp()) {
-
-        RefPtr<TabChild> child = sPreallocatedTab.get();
-        sPreallocatedTab = nullptr;
-
-        MOZ_ASSERT(!child->mTriedBrowserInit);
-
-        child->mManager = aManager;
-        child->SetTabId(aTabId);
-        child->SetTabContext(aContext);
-        child->NotifyTabContextUpdated(true);
-        return child.forget();
-    }
-
-    RefPtr<TabChild> iframe = new TabChild(aManager, aTabId,
-                                             aContext, aChromeFlags);
+    RefPtr<TabChild> iframe = new TabChild(aManager, aTabId, aContext, aChromeFlags);
     return NS_SUCCEEDED(iframe->Init()) ? iframe.forget() : nullptr;
 }
 
@@ -614,13 +532,6 @@ TabChild::DoUpdateZoomConstraints(const uint32_t& aPresShellId,
                                   const ViewID& aViewId,
                                   const Maybe<ZoomConstraints>& aConstraints)
 {
-  if (sPreallocatedTab == this) {
-    // If we're the preallocated tab, bail out because doing IPC will crash.
-    // Once we get used for something we'll get another zoom constraints update
-    // and all will be well.
-    return true;
-  }
-
   if (!mApzcTreeManager) {
     return false;
   }
@@ -779,9 +690,9 @@ TabChild::UpdateFrameType()
   MOZ_ASSERT(docShell);
 
   // TODO: Bug 1252794 - remove frameType from nsIDocShell.idl
-  docShell->SetFrameType(IsMozBrowserElement() ? nsIDocShell::FRAME_TYPE_BROWSER :
-                           HasOwnApp() ? nsIDocShell::FRAME_TYPE_APP :
-                             nsIDocShell::FRAME_TYPE_REGULAR);
+  docShell->SetFrameType(IsMozBrowserElement() ?
+                           nsIDocShell::FRAME_TYPE_BROWSER :
+                           nsIDocShell::FRAME_TYPE_REGULAR);
 }
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(TabChild)
@@ -1091,11 +1002,11 @@ TabChild::ProvideWindow(mozIDOMWindowProxy* aParent,
 {
     *aReturn = nullptr;
 
-    // If aParent is inside an <iframe mozbrowser> or <iframe mozapp> and this
-    // isn't a request to open a modal-type window, we're going to create a new
-    // <iframe mozbrowser/mozapp> and return its window here.
+    // If aParent is inside an <iframe mozbrowser> and this isn't a request to
+    // open a modal-type window, we're going to create a new <iframe mozbrowser>
+    // and return its window here.
     nsCOMPtr<nsIDocShell> docshell = do_GetInterface(aParent);
-    bool iframeMoz = (docshell && docshell->GetIsInMozBrowserOrApp() &&
+    bool iframeMoz = (docshell && docshell->GetIsInMozBrowser() &&
                       !(aChromeFlags & (nsIWebBrowserChrome::CHROME_MODAL |
                                         nsIWebBrowserChrome::CHROME_OPENAS_DIALOG |
                                         nsIWebBrowserChrome::CHROME_OPENAS_CHROME)));
@@ -1208,24 +1119,6 @@ TabChild::~TabChild()
   }
 }
 
-void
-TabChild::SetProcessNameToAppName()
-{
-  nsCOMPtr<mozIApplication> app = GetOwnApp();
-  if (!app) {
-    return;
-  }
-
-  nsAutoString appName;
-  nsresult rv = app->GetName(appName);
-  if (NS_FAILED(rv)) {
-    NS_WARNING("Failed to retrieve app name");
-    return;
-  }
-
-  ContentChild::GetSingleton()->SetProcessName(appName, true);
-}
-
 bool
 TabChild::RecvLoadURL(const nsCString& aURI,
                       const ShowInfo& aInfo)
@@ -1237,8 +1130,6 @@ TabChild::RecvLoadURL(const nsCString& aURI,
     }
 
     ApplyShowInfo(aInfo);
-
-    SetProcessNameToAppName();
   }
 
   nsresult rv =
@@ -1279,7 +1170,7 @@ TabChild::ApplyShowInfo(const ShowInfo& aInfo)
   nsCOMPtr<nsIDocShell> docShell = do_GetInterface(WebNavigation());
   if (docShell) {
     nsCOMPtr<nsIDocShellTreeItem> item = do_GetInterface(docShell);
-    if (IsMozBrowserOrApp()) {
+    if (IsMozBrowser()) {
       // B2G allows window.name to be set by changing the name attribute on the
       // <iframe mozbrowser> element. window.open calls cause this attribute to
       // be set to the correct value. A normal <xul:browser> element has no such
@@ -2135,7 +2026,7 @@ TabChild::RecvSwappedWithOtherRemoteLoader(const IPCTabContext& aContext)
   // Ignore previous value of mTriedBrowserInit since owner content has changed.
   mTriedBrowserInit = true;
   // Initialize the child side of the browser element machinery, if appropriate.
-  if (IsMozBrowserOrApp()) {
+  if (IsMozBrowser()) {
     RecvLoadRemoteScript(BROWSER_ELEMENT_CHILD_SCRIPT, true);
   }
 
@@ -2466,7 +2357,7 @@ TabChild::DeallocPRenderFrameChild(PRenderFrameChild* aFrame)
 }
 
 bool
-TabChild::InitTabChildGlobal(FrameScriptLoading aScriptLoading)
+TabChild::InitTabChildGlobal()
 {
   if (!mGlobal && !mTabChildGlobal) {
     nsCOMPtr<nsPIDOMWindowOuter> window = do_GetInterface(WebNavigation());
@@ -2490,11 +2381,11 @@ TabChild::InitTabChildGlobal(FrameScriptLoading aScriptLoading)
     root->SetParentTarget(scope);
   }
 
-  if (aScriptLoading != DONT_LOAD_SCRIPTS && !mTriedBrowserInit) {
+  if (!mTriedBrowserInit) {
     mTriedBrowserInit = true;
     // Initialize the child side of the browser element machinery,
     // if appropriate.
-    if (IsMozBrowserOrApp()) {
+    if (IsMozBrowser()) {
       RecvLoadRemoteScript(BROWSER_ELEMENT_CHILD_SCRIPT, true);
     }
   }
diff --git a/dom/ipc/TabChild.h b/dom/ipc/TabChild.h
index a812b8213a..5a09047c5d 100644
--- a/dom/ipc/TabChild.h
+++ b/dom/ipc/TabChild.h
@@ -278,13 +278,6 @@ public:
 
   nsresult Init();
 
-  /**
-   * This is expected to be called off the critical path to content
-   * startup.  This is an opportunity to load things that are slow
-   * on the critical path.
-   */
-  static void PreloadSlowThings();
-
   /** Return a TabChild with the given attributes. */
   static already_AddRefed<TabChild>
   Create(nsIContentChild* aManager, const TabId& aTabId,
@@ -697,9 +690,7 @@ private:
 
   void ActorDestroy(ActorDestroyReason why) override;
 
-  enum FrameScriptLoading { DONT_LOAD_SCRIPTS, DEFAULT_LOAD_SCRIPTS };
-
-  bool InitTabChildGlobal(FrameScriptLoading aScriptLoading = DEFAULT_LOAD_SCRIPTS);
+  bool InitTabChildGlobal();
 
   bool InitRenderingState(const TextureFactoryIdentifier& aTextureFactoryIdentifier,
                           const uint64_t& aLayersId,
@@ -707,8 +698,6 @@ private:
 
   void DestroyWindow();
 
-  void SetProcessNameToAppName();
-
   void ApplyShowInfo(const ShowInfo& aInfo);
 
   bool HasValidInnerSize();
diff --git a/dom/ipc/TabContext.cpp b/dom/ipc/TabContext.cpp
index b313da0ffa..fd434fe0cb 100644
--- a/dom/ipc/TabContext.cpp
+++ b/dom/ipc/TabContext.cpp
@@ -7,7 +7,6 @@
 #include "mozilla/dom/PTabContext.h"
 #include "mozilla/dom/TabParent.h"
 #include "mozilla/dom/TabChild.h"
-#include "nsIAppsService.h"
 #include "nsIScriptSecurityManager.h"
 #include "nsServiceManagerUtils.h"
 
@@ -23,7 +22,7 @@ TabContext::TabContext()
   : mIsPrerendered(false)
   , mInitialized(false)
   , mIsMozBrowserElement(false)
-  , mContainingAppId(NO_APP_ID)
+  , mOriginAttributes()
   , mShowAccelerators(UIStateChangeType_NoChange)
   , mShowFocusRings(UIStateChangeType_NoChange)
 {
@@ -36,117 +35,9 @@ TabContext::IsMozBrowserElement() const
 }
 
 bool
-TabContext::IsIsolatedMozBrowserElement() const
+TabContext::IsMozBrowser() const
 {
-  return mOriginAttributes.mInIsolatedMozBrowser;
-}
-
-bool
-TabContext::IsMozBrowserOrApp() const
-{
-  return HasOwnApp() || IsMozBrowserElement();
-}
-
-uint32_t
-TabContext::OwnAppId() const
-{
-  return mOriginAttributes.mAppId;
-}
-
-already_AddRefed<mozIApplication>
-TabContext::GetOwnApp() const
-{
-  nsCOMPtr<mozIApplication> ownApp = mOwnApp;
-  return ownApp.forget();
-}
-
-bool
-TabContext::HasOwnApp() const
-{
-  nsCOMPtr<mozIApplication> ownApp = GetOwnApp();
-  return !!ownApp;
-}
-
-uint32_t
-TabContext::BrowserOwnerAppId() const
-{
-  if (IsMozBrowserElement()) {
-    return mContainingAppId;
-  }
-  return NO_APP_ID;
-}
-
-already_AddRefed<mozIApplication>
-TabContext::GetBrowserOwnerApp() const
-{
-  nsCOMPtr<mozIApplication> ownerApp;
-  if (IsMozBrowserElement()) {
-    ownerApp = mContainingApp;
-  }
-  return ownerApp.forget();
-}
-
-bool
-TabContext::HasBrowserOwnerApp() const
-{
-  nsCOMPtr<mozIApplication> ownerApp = GetBrowserOwnerApp();
-  return !!ownerApp;
-}
-
-uint32_t
-TabContext::AppOwnerAppId() const
-{
-  if (HasOwnApp()) {
-    return mContainingAppId;
-  }
-  return NO_APP_ID;
-}
-
-already_AddRefed<mozIApplication>
-TabContext::GetAppOwnerApp() const
-{
-  nsCOMPtr<mozIApplication> ownerApp;
-  if (HasOwnApp()) {
-    ownerApp = mContainingApp;
-  }
-  return ownerApp.forget();
-}
-
-bool
-TabContext::HasAppOwnerApp() const
-{
-  nsCOMPtr<mozIApplication> ownerApp = GetAppOwnerApp();
-  return !!ownerApp;
-}
-
-uint32_t
-TabContext::OwnOrContainingAppId() const
-{
-  if (HasOwnApp()) {
-    return mOriginAttributes.mAppId;
-  }
-
-  return mContainingAppId;
-}
-
-already_AddRefed<mozIApplication>
-TabContext::GetOwnOrContainingApp() const
-{
-  nsCOMPtr<mozIApplication> ownOrContainingApp;
-  if (HasOwnApp()) {
-    ownOrContainingApp = mOwnApp;
-  } else {
-    ownOrContainingApp = mContainingApp;
-  }
-
-  return ownOrContainingApp.forget();
-}
-
-bool
-TabContext::HasOwnOrContainingApp() const
-{
-  nsCOMPtr<mozIApplication> ownOrContainingApp = GetOwnOrContainingApp();
-  return !!ownOrContainingApp;
+  return IsMozBrowserElement();
 }
 
 bool
@@ -174,9 +65,7 @@ TabContext::UpdateTabContextAfterSwap(const TabContext& aContext)
 
   // The only permissable change is to `mIsMozBrowserElement`.  All other fields
   // must match for the change to be accepted.
-  if (aContext.OwnAppId() != OwnAppId() ||
-      aContext.mContainingAppId != mContainingAppId ||
-      aContext.mOriginAttributes != mOriginAttributes) {
+  if (aContext.mOriginAttributes != mOriginAttributes) {
     return false;
   }
 
@@ -205,42 +94,19 @@ TabContext::ShowFocusRings() const
 bool
 TabContext::SetTabContext(bool aIsMozBrowserElement,
                           bool aIsPrerendered,
-                          mozIApplication* aOwnApp,
-                          mozIApplication* aAppFrameOwnerApp,
                           UIStateChangeType aShowAccelerators,
                           UIStateChangeType aShowFocusRings,
                           const DocShellOriginAttributes& aOriginAttributes)
 {
   NS_ENSURE_FALSE(mInitialized, false);
 
-  // Get ids for both apps and only write to our member variables after we've
-  // verified that this worked.
-  uint32_t ownAppId = NO_APP_ID;
-  if (aOwnApp) {
-    nsresult rv = aOwnApp->GetLocalId(&ownAppId);
-    NS_ENSURE_SUCCESS(rv, false);
-    NS_ENSURE_TRUE(ownAppId != NO_APP_ID, false);
-  }
-
-  uint32_t containingAppId = NO_APP_ID;
-  if (aAppFrameOwnerApp) {
-    nsresult rv = aAppFrameOwnerApp->GetLocalId(&containingAppId);
-    NS_ENSURE_SUCCESS(rv, false);
-    NS_ENSURE_TRUE(containingAppId != NO_APP_ID, false);
-  }
-
-  // Veryify that app id matches mAppId passed in originAttributes
-  MOZ_RELEASE_ASSERT((aOwnApp && aOriginAttributes.mAppId == ownAppId) ||
-                     (aAppFrameOwnerApp && aOriginAttributes.mAppId == containingAppId) ||
-                     aOriginAttributes.mAppId == NO_APP_ID);
+  // Verify that app id matches mAppId passed in originAttributes
+  MOZ_RELEASE_ASSERT(aOriginAttributes.mAppId == NO_APP_ID);
 
   mInitialized = true;
   mIsMozBrowserElement = aIsMozBrowserElement;
   mIsPrerendered = aIsPrerendered;
   mOriginAttributes = aOriginAttributes;
-  mContainingAppId = containingAppId;
-  mOwnApp = aOwnApp;
-  mContainingApp = aAppFrameOwnerApp;
   mShowAccelerators = aShowAccelerators;
   mShowFocusRings = aShowFocusRings;
   return true;
@@ -250,31 +116,17 @@ IPCTabContext
 TabContext::AsIPCTabContext() const
 {
   return IPCTabContext(FrameIPCTabContext(mOriginAttributes,
-                                          mContainingAppId,
                                           mIsMozBrowserElement,
                                           mIsPrerendered,
                                           mShowAccelerators,
                                           mShowFocusRings));
 }
 
-static already_AddRefed<mozIApplication>
-GetAppForId(uint32_t aAppId)
-{
-  nsCOMPtr<nsIAppsService> appsService = do_GetService(APPS_SERVICE_CONTRACTID);
-  NS_ENSURE_TRUE(appsService, nullptr);
-
-  nsCOMPtr<mozIApplication> app;
-  appsService->GetAppByLocalId(aAppId, getter_AddRefs(app));
-
-  return app.forget();
-}
-
 MaybeInvalidTabContext::MaybeInvalidTabContext(const IPCTabContext& aParams)
   : mInvalidReason(nullptr)
 {
   bool isMozBrowserElement = false;
   bool isPrerendered = false;
-  uint32_t containingAppId = NO_APP_ID;
   DocShellOriginAttributes originAttributes;
   UIStateChangeType showAccelerators = UIStateChangeType_NoChange;
   UIStateChangeType showFocusRings = UIStateChangeType_NoChange;
@@ -324,11 +176,6 @@ MaybeInvalidTabContext::MaybeInvalidTabContext(const IPCTabContext& aParams)
       // opener app.
       isMozBrowserElement = ipcContext.isMozBrowserElement();
       originAttributes = context->mOriginAttributes;
-      if (isMozBrowserElement) {
-        containingAppId = context->OwnOrContainingAppId();
-      } else {
-        containingAppId = context->mContainingAppId;
-      }
       break;
     }
     case IPCTabContext::TFrameIPCTabContext: {
@@ -337,7 +184,6 @@ MaybeInvalidTabContext::MaybeInvalidTabContext(const IPCTabContext& aParams)
 
       isMozBrowserElement = ipcContext.isMozBrowserElement();
       isPrerendered = ipcContext.isPrerendered();
-      containingAppId = ipcContext.frameOwnerAppId();
       showAccelerators = ipcContext.showAccelerators();
       showFocusRings = ipcContext.showFocusRings();
       originAttributes = ipcContext.originAttributes();
@@ -352,7 +198,6 @@ MaybeInvalidTabContext::MaybeInvalidTabContext(const IPCTabContext& aParams)
         return;
       }
 
-      containingAppId = NO_APP_ID;
       break;
     }
     default: {
@@ -360,28 +205,9 @@ MaybeInvalidTabContext::MaybeInvalidTabContext(const IPCTabContext& aParams)
     }
   }
 
-  nsCOMPtr<mozIApplication> ownApp;
-  if (!isMozBrowserElement) {
-    // mAppId corresponds to OwnOrContainingAppId; if isMozBrowserElement is
-    // false then it's ownApp otherwise it's containingApp
-    ownApp = GetAppForId(originAttributes.mAppId);
-    if ((ownApp == nullptr) != (originAttributes.mAppId == NO_APP_ID)) {
-      mInvalidReason = "Got an ownAppId that didn't correspond to an app.";
-      return;
-    }
-  }
-
-  nsCOMPtr<mozIApplication> containingApp = GetAppForId(containingAppId);
-  if ((containingApp == nullptr) != (containingAppId == NO_APP_ID)) {
-    mInvalidReason = "Got a containingAppId that didn't correspond to an app.";
-    return;
-  }
-
   bool rv;
   rv = mTabContext.SetTabContext(isMozBrowserElement,
                                  isPrerendered,
-                                 ownApp,
-                                 containingApp,
                                  showAccelerators,
                                  showFocusRings,
                                  originAttributes);
diff --git a/dom/ipc/TabContext.h b/dom/ipc/TabContext.h
index e0b6f0d963..8bb21dc1e0 100644
--- a/dom/ipc/TabContext.h
+++ b/dom/ipc/TabContext.h
@@ -6,7 +6,6 @@
 #ifndef mozilla_dom_TabContext_h
 #define mozilla_dom_TabContext_h
 
-#include "mozIApplication.h"
 #include "nsCOMPtr.h"
 #include "mozilla/BasePrincipal.h"
 #include "nsPIDOMWindow.h"
@@ -18,9 +17,7 @@ namespace dom {
 class IPCTabContext;
 
 /**
- * TabContext encapsulates information about an iframe that may be a mozbrowser
- * or mozapp.  You can ask whether a TabContext corresponds to a mozbrowser or
- * mozapp, get the app that contains the browser, and so on.
+ * TabContext encapsulates information about an iframe that may be a mozbrowser.
  *
  * TabParent and TabChild both inherit from TabContext, and you can also have
  * standalone TabContext objects.
@@ -37,91 +34,29 @@ public:
   /* (The implicit copy-constructor and operator= are fine.) */
 
   /**
-   * Generates IPCTabContext of type BrowserFrameIPCTabContext or
-   * AppFrameIPCTabContext from this TabContext's information.
+   * Generates IPCTabContext of type BrowserFrameIPCTabContext from this
+   * TabContext's information.
    */
   IPCTabContext AsIPCTabContext() const;
 
   /**
    * Does this TabContext correspond to a mozbrowser?
    *
-   * <iframe mozbrowser mozapp> and <xul:browser> are not considered to be
-   * mozbrowser elements.
-   *
-   * If IsMozBrowserElement() is true, HasOwnApp() and HasAppOwnerApp() are
-   * guaranteed to be false.
-   *
-   * If IsMozBrowserElement() is false, HasBrowserOwnerApp() is guaranteed to be
-   * false.
+   * <iframe mozbrowser> is a mozbrowser element, but <xul:browser> is not.
    */
   bool IsMozBrowserElement() const;
 
   /**
-   * Does this TabContext correspond to an isolated mozbrowser?
-   *
-   * <iframe mozbrowser mozapp> and <xul:browser> are not considered to be
-   * mozbrowser elements.  <iframe mozbrowser noisolation> does not count as
-   * isolated since isolation is disabled.  Isolation can only be disabled by
-   * chrome pages.
+   * Does this TabContext correspond to a mozbrowser?  This is equivalent to
+   * IsMozBrowserElement().  Returns false for <xul:browser>, which isn't a
+   * mozbrowser.
    */
-  bool IsIsolatedMozBrowserElement() const;
-
-  /**
-   * Does this TabContext correspond to a mozbrowser or mozapp?  This is
-   * equivalent to IsMozBrowserElement() || HasOwnApp().  Returns false for
-   * <xul:browser>, which is neither a mozbrowser nor a mozapp.
-   */
-  bool IsMozBrowserOrApp() const;
-
-  /**
-   * OwnAppId() returns the id of the app which directly corresponds to this
-   * context's frame.  GetOwnApp() returns the corresponding app object, and
-   * HasOwnApp() returns true iff GetOwnApp() would return a non-null value.
-   *
-   * If HasOwnApp() is true, IsMozBrowserElement() is guaranteed to be
-   * false.
-   */
-  uint32_t OwnAppId() const;
-  already_AddRefed<mozIApplication> GetOwnApp() const;
-  bool HasOwnApp() const;
-
-  /**
-   * BrowserOwnerAppId() gets the ID of the app which contains this browser
-   * frame.  If this is not a mozbrowser frame (if !IsMozBrowserElement()), then
-   * BrowserOwnerAppId() is guaranteed to return NO_APP_ID.
-   *
-   * Even if we are a browser frame, BrowserOwnerAppId() may still return
-   * NO_APP_ID, if this browser frame is not contained inside an app.
-   */
-  uint32_t BrowserOwnerAppId() const;
-  already_AddRefed<mozIApplication> GetBrowserOwnerApp() const;
-  bool HasBrowserOwnerApp() const;
-
-  /**
-   * AppOwnerAppId() gets the ID of the app which contains this app frame.  If
-   * this is not an app frame (i.e., if !HasOwnApp()), then AppOwnerAppId() is
-   * guaranteed to return NO_APP_ID.
-   *
-   * Even if we are an app frame, AppOwnerAppId() may still return NO_APP_ID, if
-   * this app frame is not contained inside an app.
-   */
-  uint32_t AppOwnerAppId() const;
-  already_AddRefed<mozIApplication> GetAppOwnerApp() const;
-  bool HasAppOwnerApp() const;
-
-  /**
-   * OwnOrContainingAppId() gets the ID of this frame, if HasOwnApp().  If this
-   * frame does not have its own app, it gets the ID of the app which contains
-   * this frame (i.e., the result of {Browser,App}OwnerAppId(), as applicable).
-   */
-  uint32_t OwnOrContainingAppId() const;
-  already_AddRefed<mozIApplication> GetOwnOrContainingApp() const;
-  bool HasOwnOrContainingApp() const;
+  bool IsMozBrowser() const;
 
   /**
    * OriginAttributesRef() returns the DocShellOriginAttributes of this frame to
    * the caller. This is used to store any attribute associated with the frame's
-   * docshell, such as the AppId.
+   * docshell.
    */
   const DocShellOriginAttributes& OriginAttributesRef() const;
 
@@ -150,17 +85,8 @@ protected:
    */
   void SetPrivateBrowsingAttributes(bool aIsPrivateBrowsing);
 
-  /**
-   * Set the TabContext for this frame. This can either be:
-   *  - an app frame (with the given own app) inside the given owner app. Either
-   *    apps can be null.
-   *  - a browser frame inside the given owner app (which may be null).
-   *  - a non-browser, non-app frame. Both own app and owner app should be null.
-   */
   bool SetTabContext(bool aIsMozBrowserElement,
                      bool aIsPrerendered,
-                     mozIApplication* aOwnApp,
-                     mozIApplication* aAppFrameOwnerApp,
                      UIStateChangeType aShowAccelerators,
                      UIStateChangeType aShowFocusRings,
                      const DocShellOriginAttributes& aOriginAttributes);
@@ -190,29 +116,11 @@ private:
   /**
    * Whether this TabContext corresponds to a mozbrowser.
    *
-   * <iframe mozbrowser mozapp> and <xul:browser> are not considered to be
+   * <iframe mozbrowser> and <xul:browser> are not considered to be
    * mozbrowser elements.
    */
   bool mIsMozBrowserElement;
 
-  /**
-   * This TabContext's own app.  If this is non-null, then this
-   * TabContext corresponds to an app, and mIsMozBrowserElement must be false.
-   */
-  nsCOMPtr<mozIApplication> mOwnApp;
-
-  /**
-   * This TabContext's containing app.  If mIsMozBrowserElement, this
-   * corresponds to the app which contains the browser frame; otherwise, this
-   * corresponds to the app which contains the app frame.
-   */
-  nsCOMPtr<mozIApplication> mContainingApp;
-
-  /*
-   * Cache of mContainingApp->GetLocalId().
-   */
-  uint32_t mContainingAppId;
-
   /**
    * DocShellOriginAttributes of the top level tab docShell
    */
@@ -241,16 +149,12 @@ public:
   bool
   SetTabContext(bool aIsMozBrowserElement,
                 bool aIsPrerendered,
-                mozIApplication* aOwnApp,
-                mozIApplication* aAppFrameOwnerApp,
                 UIStateChangeType aShowAccelerators,
                 UIStateChangeType aShowFocusRings,
                 const DocShellOriginAttributes& aOriginAttributes)
   {
     return TabContext::SetTabContext(aIsMozBrowserElement,
                                      aIsPrerendered,
-                                     aOwnApp,
-                                     aAppFrameOwnerApp,
                                      aShowAccelerators,
                                      aShowFocusRings,
                                      aOriginAttributes);
@@ -261,10 +165,9 @@ public:
  * MaybeInvalidTabContext is a simple class that lets you transform an
  * IPCTabContext into a TabContext.
  *
- * The issue is that an IPCTabContext is not necessarily valid; for example, it
- * might specify an app-id which doesn't exist.  So to convert an IPCTabContext
- * into a TabContext, you construct a MaybeInvalidTabContext, check whether it's
- * valid, and, if so, read out your TabContext.
+ * The issue is that an IPCTabContext is not necessarily valid.  So to convert
+ * an IPCTabContext into a TabContext, you construct a MaybeInvalidTabContext,
+ * check whether it's valid, and, if so, read out your TabContext.
  *
  * Example usage:
  *
diff --git a/dom/ipc/TabParent.cpp b/dom/ipc/TabParent.cpp
index a3d2556ae1..3c58dbecc3 100644
--- a/dom/ipc/TabParent.cpp
+++ b/dom/ipc/TabParent.cpp
@@ -9,7 +9,6 @@
 
 #include "AudioChannelService.h"
 #include "AppProcessChecker.h"
-#include "mozIApplication.h"
 #ifdef ACCESSIBILITY
 #include "mozilla/a11y/DocAccessibleParent.h"
 #include "nsAccessibilityService.h"
@@ -2940,8 +2939,6 @@ public:
   NS_IMETHOD GetUsePrivateBrowsing(bool*) NO_IMPL
   NS_IMETHOD SetUsePrivateBrowsing(bool) NO_IMPL
   NS_IMETHOD SetPrivateBrowsing(bool) NO_IMPL
-  NS_IMETHOD GetIsInIsolatedMozBrowserElement(bool*) NO_IMPL
-  NS_IMETHOD GetAppId(uint32_t*) NO_IMPL
   NS_IMETHOD GetOriginAttributes(JS::MutableHandleValue) NO_IMPL
   NS_IMETHOD GetUseRemoteTabs(bool*) NO_IMPL
   NS_IMETHOD SetRemoteTabs(bool) NO_IMPL
diff --git a/dom/ipc/jar.mn b/dom/ipc/jar.mn
index 86920f0742..30288ecce6 100644
--- a/dom/ipc/jar.mn
+++ b/dom/ipc/jar.mn
@@ -10,4 +10,3 @@ toolkit.jar:
         content/global/BrowserElementCopyPaste.js (../browser-element/BrowserElementCopyPaste.js)
         content/global/extensions.js (extensions.js)
         content/global/manifestMessages.js (manifestMessages.js)
-        content/global/preload.js (preload.js)
diff --git a/dom/ipc/moz.build b/dom/ipc/moz.build
index 0aa3450e47..d7f834538e 100644
--- a/dom/ipc/moz.build
+++ b/dom/ipc/moz.build
@@ -37,7 +37,6 @@ EXPORTS.mozilla.dom += [
 
 EXPORTS.mozilla += [
     'AppProcessChecker.h',
-    'PreallocatedProcessManager.h',
     'ProcessHangMonitor.h',
     'ProcessHangMonitorIPC.h',
     'ProcessPriorityManager.h',
@@ -55,7 +54,6 @@ UNIFIED_SOURCES += [
     'nsIContentChild.cpp',
     'nsIContentParent.cpp',
     'PermissionMessageUtils.cpp',
-    'PreallocatedProcessManager.cpp',
     'ProcessPriorityManager.cpp',
     'ScreenManagerParent.cpp',
     'StructuredCloneData.cpp',
diff --git a/dom/ipc/nsIContentChild.cpp b/dom/ipc/nsIContentChild.cpp
index f604dc1a58..84727a8051 100644
--- a/dom/ipc/nsIContentChild.cpp
+++ b/dom/ipc/nsIContentChild.cpp
@@ -43,7 +43,6 @@ nsIContentChild::AllocPBrowserChild(const TabId& aTabId,
                                     const IPCTabContext& aContext,
                                     const uint32_t& aChromeFlags,
                                     const ContentParentId& aCpID,
-                                    const bool& aIsForApp,
                                     const bool& aIsForBrowser)
 {
   // We'll happily accept any kind of IPCTabContext here; we don't need to
diff --git a/dom/ipc/nsIContentChild.h b/dom/ipc/nsIContentChild.h
index 59dffe6b69..2b563a81e5 100644
--- a/dom/ipc/nsIContentChild.h
+++ b/dom/ipc/nsIContentChild.h
@@ -68,7 +68,6 @@ public:
                           const IPCTabContext& aContext,
                           const uint32_t& aChromeFlags,
                           const ContentParentId& aCpID,
-                          const bool& aIsForApp,
                           const bool& aIsForBrowser) = 0;
 
   virtual mozilla::ipc::PFileDescriptorSetChild*
@@ -85,7 +84,6 @@ protected:
                                             const IPCTabContext& aContext,
                                             const uint32_t& aChromeFlags,
                                             const ContentParentId& aCpId,
-                                            const bool& aIsForApp,
                                             const bool& aIsForBrowser);
   virtual bool DeallocPBrowserChild(PBrowserChild*);
 
diff --git a/dom/ipc/nsIContentParent.cpp b/dom/ipc/nsIContentParent.cpp
index 2ff4fcdfc8..fdb6734e9c 100644
--- a/dom/ipc/nsIContentParent.cpp
+++ b/dom/ipc/nsIContentParent.cpp
@@ -122,11 +122,9 @@ nsIContentParent::AllocPBrowserParent(const TabId& aTabId,
                                       const IPCTabContext& aContext,
                                       const uint32_t& aChromeFlags,
                                       const ContentParentId& aCpId,
-                                      const bool& aIsForApp,
                                       const bool& aIsForBrowser)
 {
   Unused << aCpId;
-  Unused << aIsForApp;
   Unused << aIsForBrowser;
 
   if (!CanOpenBrowser(aContext)) {
diff --git a/dom/ipc/nsIContentParent.h b/dom/ipc/nsIContentParent.h
index 6fae9060cb..c883e23695 100644
--- a/dom/ipc/nsIContentParent.h
+++ b/dom/ipc/nsIContentParent.h
@@ -60,7 +60,6 @@ public:
   BlobParent* GetOrCreateActorForBlobImpl(BlobImpl* aImpl);
 
   virtual ContentParentId ChildID() const = 0;
-  virtual bool IsForApp() const = 0;
   virtual bool IsForBrowser() const = 0;
 
   MOZ_MUST_USE virtual PBlobParent*
@@ -73,7 +72,6 @@ public:
                           const IPCTabContext& context,
                           const uint32_t& chromeFlags,
                           const ContentParentId& aCpId,
-                          const bool& aIsForApp,
                           const bool& aIsForBrowser) = 0;
 
   virtual bool IsContentParent() const { return false; }
@@ -99,7 +97,6 @@ protected: // IPDL methods
                                               const IPCTabContext& aContext,
                                               const uint32_t& aChromeFlags,
                                               const ContentParentId& aCpId,
-                                              const bool& aIsForApp,
                                               const bool& aIsForBrowser);
   virtual bool DeallocPBrowserParent(PBrowserParent* frame);
 
diff --git a/dom/ipc/preload.js b/dom/ipc/preload.js
deleted file mode 100644
index e85189d8b7..0000000000
--- a/dom/ipc/preload.js
+++ /dev/null
@@ -1,129 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-// Preload some things, in an attempt to make app startup faster.
-//
-// This script is run when the preallocated process starts.  It is injected as
-// a frame script.
-
-var BrowserElementIsPreloaded = true;
-
-var DoPreloadPostfork = function(aCallback) {
-  Services.obs.addObserver({
-    _callback: aCallback,
-
-    observe: function() {
-      this._callback();
-      Services.obs.removeObserver(this, "preload-postfork");
-    }
-  }, "preload-postfork", false);
-};
-
-(function (global) {
-  "use strict";
-
-  let Cu = Components.utils;
-  let Cc = Components.classes;
-  let Ci = Components.interfaces;
-
-  Cu.import("resource://gre/modules/AppsUtils.jsm");
-  Cu.import("resource://gre/modules/BrowserElementPromptService.jsm");
-  Cu.import("resource://gre/modules/DOMRequestHelper.jsm");
-  Cu.import("resource://gre/modules/FileUtils.jsm");
-  Cu.import("resource://gre/modules/Geometry.jsm");
-  Cu.import("resource://gre/modules/IndexedDBHelper.jsm");
-  Cu.import("resource://gre/modules/NetUtil.jsm");
-  Cu.import("resource://gre/modules/Services.jsm");
-  Cu.import("resource://gre/modules/SettingsDB.jsm");
-  Cu.import("resource://gre/modules/XPCOMUtils.jsm");
-
-  Cc["@mozilla.org/appshell/appShellService;1"].getService(Ci["nsIAppShellService"]);
-  Cc["@mozilla.org/appshell/window-mediator;1"].getService(Ci["nsIWindowMediator"]);
-  Cc["@mozilla.org/categorymanager;1"].getService(Ci["nsICategoryManager"]);
-  Cc["@mozilla.org/childprocessmessagemanager;1"].getService(Ci["nsIMessageSender"]);
-  Cc["@mozilla.org/consoleservice;1"].getService(Ci["nsIConsoleService"]);
-  Cc["@mozilla.org/docshell/urifixup;1"].getService(Ci["nsIURIFixup"]);
-  Cc["@mozilla.org/dom/dom-request-service;1"].getService(Ci["nsIDOMRequestService"]);
-  Cc["@mozilla.org/embedcomp/prompt-service;1"].getService(Ci["nsIPromptService"]);
-  Cc["@mozilla.org/embedcomp/window-watcher;1"].getService(Ci["nsIWindowWatcher"]);
-  Cc["@mozilla.org/eventlistenerservice;1"].getService(Ci["nsIEventListenerService"]);
-  Cc["@mozilla.org/focus-manager;1"].getService(Ci["nsIFocusManager"]);
-  Cc["@mozilla.org/intl/nslocaleservice;1"].getService(Ci["nsILocaleService"]);
-  Cc["@mozilla.org/intl/stringbundle;1"].getService(Ci["nsIStringBundleService"]);
-  Cc["@mozilla.org/layout/content-policy;1"].getService(Ci["nsIContentPolicy"]);
-  Cc["@mozilla.org/message-loop;1"].getService(Ci["nsIMessageLoop"]);
-  Cc["@mozilla.org/moz/jssubscript-loader;1"].getService(Ci["mozIJSSubScriptLoader"]);
-  Cc["@mozilla.org/network/application-cache-service;1"].getService(Ci["nsIApplicationCacheService"]);
-  Cc["@mozilla.org/network/dns-service;1"].getService(Ci["nsIDNSService"]);
-  Cc["@mozilla.org/network/effective-tld-service;1"].getService(Ci["nsIEffectiveTLDService"]);
-  Cc["@mozilla.org/network/idn-service;1"].getService(Ci["nsIIDNService"]);
-  Cc["@mozilla.org/network/io-service;1"].getService(Ci["nsIIOService2"]);
-  Cc["@mozilla.org/network/mime-hdrparam;1"].getService(Ci["nsIMIMEHeaderParam"]);
-  Cc["@mozilla.org/network/socket-transport-service;1"].getService(Ci["nsISocketTransportService"]);
-  Cc["@mozilla.org/network/stream-transport-service;1"].getService(Ci["nsIStreamTransportService"]);
-  Cc["@mozilla.org/network/url-parser;1?auth=maybe"].getService(Ci["nsIURLParser"]);
-  Cc["@mozilla.org/network/url-parser;1?auth=no"].getService(Ci["nsIURLParser"]);
-  Cc["@mozilla.org/network/url-parser;1?auth=yes"].getService(Ci["nsIURLParser"]);
-  Cc["@mozilla.org/observer-service;1"].getService(Ci["nsIObserverService"]);
-  Cc["@mozilla.org/preferences-service;1"].getService(Ci["nsIPrefBranch"]);
-  Cc["@mozilla.org/scriptsecuritymanager;1"].getService(Ci["nsIScriptSecurityManager"]);
-  Cc["@mozilla.org/storage/service;1"].getService(Ci["mozIStorageService"]);
-  Cc["@mozilla.org/system-info;1"].getService(Ci["nsIPropertyBag2"]);
-  Cc["@mozilla.org/thread-manager;1"].getService(Ci["nsIThreadManager"]);
-  Cc["@mozilla.org/toolkit/app-startup;1"].getService(Ci["nsIAppStartup"]);
-  Cc["@mozilla.org/uriloader;1"].getService(Ci["nsIURILoader"]);
-  Cc["@mozilla.org/cspcontext;1"].createInstance(Ci["nsIContentSecurityPolicy"]);
-  Cc["@mozilla.org/settingsManager;1"].createInstance(Ci["nsISupports"]);
-
-  /* Applications Specific Helper */
-  try {
-    if (Services.prefs.getBoolPref("dom.sysmsg.enabled")) {
-      Cc["@mozilla.org/system-message-manager;1"].getService(Ci["nsIDOMNavigatorSystemMessages"]);
-    }
-  } catch(e) {
-  }
-
-  try {
-    if (Services.prefs.getBoolPref("dom.mozInputMethod.enabled")) {
-      Services.scriptloader.loadSubScript("chrome://global/content/forms.js", global);
-    }
-  } catch (e) {
-  }
-
-  Services.scriptloader.loadSubScript("chrome://global/content/BrowserElementCopyPaste.js", global);
-  Services.scriptloader.loadSubScript("chrome://global/content/BrowserElementChildPreload.js", global);
-
-  Services.io.getProtocolHandler("app");
-  Services.io.getProtocolHandler("default");
-
-  // Register an observer for topic "preload_postfork" after we fork a content
-  // process.
-  DoPreloadPostfork(function () {
-    // Load AppsServiceChild.jsm after fork since it sends an async message to
-    // the chrome process in its init() function.
-    Cu.import("resource://gre/modules/AppsServiceChild.jsm");
-
-    // Load nsIAppsService after fork since its implementation loads
-    // AppsServiceChild.jsm
-    Cc["@mozilla.org/AppsService;1"].getService(Ci["nsIAppsService"]);
-
-    // Load nsICookieService after fork since it sends an IPC constructor
-    // message to the chrome process.
-    Cc["@mozilla.org/cookieService;1"].getService(Ci["nsICookieService"]);
-
-    // Load nsIPermissionManager after fork since it sends a message to the
-    // chrome process to read permissions.
-    Cc["@mozilla.org/permissionmanager;1"].getService(Ci["nsIPermissionManager"]);
-
-    // Load nsIProtocolProxyService after fork since it asynchronously accesses
-    // the "Proxy Resolution" thread after it's frozen.
-    Cc["@mozilla.org/network/protocol-proxy-service;1"].getService(Ci["nsIProtocolProxyService"]);
-
-    // Call docShell.createAboutBlankContentViewer() after fork since it has IPC
-    // activity in the PCompositor protocol.
-    docShell.createAboutBlankContentViewer(null);
-    docShell.isActive = false;
-  });
-})(this);
-
diff --git a/dom/media/MediaManager.cpp b/dom/media/MediaManager.cpp
index 0270643cbd..970ece733b 100644
--- a/dom/media/MediaManager.cpp
+++ b/dom/media/MediaManager.cpp
@@ -1893,29 +1893,15 @@ MediaManager::NotifyRecordingStatusChange(nsPIDOMWindowInner* aWindow,
   props->SetPropertyAsBool(NS_LITERAL_STRING("isAudio"), aIsAudio);
   props->SetPropertyAsBool(NS_LITERAL_STRING("isVideo"), aIsVideo);
 
-  bool isApp = false;
-  nsString requestURL;
+  nsCString pageURL;
+  nsCOMPtr<nsIURI> docURI = aWindow->GetDocumentURI();
+  NS_ENSURE_TRUE(docURI, NS_ERROR_FAILURE);
 
-  if (nsCOMPtr<nsIDocShell> docShell = aWindow->GetDocShell()) {
-    isApp = docShell->GetIsApp();
-    if (isApp) {
-      nsresult rv = docShell->GetAppManifestURL(requestURL);
-      NS_ENSURE_SUCCESS(rv, rv);
-    }
-  }
+  nsresult rv = docURI->GetSpec(pageURL);
+  NS_ENSURE_SUCCESS(rv, rv);
 
-  if (!isApp) {
-    nsCString pageURL;
-    nsCOMPtr<nsIURI> docURI = aWindow->GetDocumentURI();
-    NS_ENSURE_TRUE(docURI, NS_ERROR_FAILURE);
+  NS_ConvertUTF8toUTF16 requestURL(pageURL);
 
-    nsresult rv = docURI->GetSpec(pageURL);
-    NS_ENSURE_SUCCESS(rv, rv);
-
-    requestURL = NS_ConvertUTF8toUTF16(pageURL);
-  }
-
-  props->SetPropertyAsBool(NS_LITERAL_STRING("isApp"), isApp);
   props->SetPropertyAsAString(NS_LITERAL_STRING("requestURL"), requestURL);
 
   obs->NotifyObservers(static_cast<nsIPropertyBag2*>(props),
diff --git a/dom/moz.build b/dom/moz.build
index 446fc25126..585dcce59c 100644
--- a/dom/moz.build
+++ b/dom/moz.build
@@ -29,7 +29,6 @@ interfaces = [
     'permission',
     'svg',
     'smil',
-    'apps',
     'push',
 ]
 
diff --git a/dom/network/TCPServerSocketParent.cpp b/dom/network/TCPServerSocketParent.cpp
index 8e05c6088f..91238e0349 100644
--- a/dom/network/TCPServerSocketParent.cpp
+++ b/dom/network/TCPServerSocketParent.cpp
@@ -67,25 +67,13 @@ TCPServerSocketParent::Init()
 uint32_t
 TCPServerSocketParent::GetAppId()
 {
-  const PContentParent *content = Manager()->Manager();
-  if (PBrowserParent* browser = SingleManagedOrNull(content->ManagedPBrowserParent())) {
-    TabParent *tab = TabParent::GetFrom(browser);
-    return tab->OwnAppId();
-  } else {
-    return nsIScriptSecurityManager::UNKNOWN_APP_ID;
-  }
+  return nsIScriptSecurityManager::UNKNOWN_APP_ID;
 }
 
 bool
 TCPServerSocketParent::GetInIsolatedMozBrowser()
 {
-  const PContentParent *content = Manager()->Manager();
-  if (PBrowserParent* browser = SingleManagedOrNull(content->ManagedPBrowserParent())) {
-    TabParent *tab = TabParent::GetFrom(browser);
-    return tab->IsIsolatedMozBrowserElement();
-  } else {
-    return false;
-  }
+  return false;
 }
 
 nsresult
diff --git a/dom/network/TCPSocketParent.cpp b/dom/network/TCPSocketParent.cpp
index 0e7f0e17ae..d8bd95576e 100644
--- a/dom/network/TCPSocketParent.cpp
+++ b/dom/network/TCPSocketParent.cpp
@@ -73,25 +73,13 @@ TCPSocketParentBase::~TCPSocketParentBase()
 uint32_t
 TCPSocketParent::GetAppId()
 {
-  const PContentParent *content = Manager()->Manager();
-  if (PBrowserParent* browser = SingleManagedOrNull(content->ManagedPBrowserParent())) {
-    TabParent *tab = TabParent::GetFrom(browser);
-    return tab->OwnAppId();
-  } else {
-    return nsIScriptSecurityManager::UNKNOWN_APP_ID;
-  }
-};
+  return nsIScriptSecurityManager::UNKNOWN_APP_ID;
+}
 
 bool
 TCPSocketParent::GetInIsolatedMozBrowser()
 {
-  const PContentParent *content = Manager()->Manager();
-  if (PBrowserParent* browser = SingleManagedOrNull(content->ManagedPBrowserParent())) {
-    TabParent *tab = TabParent::GetFrom(browser);
-    return tab->IsIsolatedMozBrowserElement();
-  } else {
-    return false;
-  }
+  return false;
 }
 
 void
@@ -225,20 +213,11 @@ TCPSocketParent::RecvOpenBind(const nsCString& aRemoteHost,
     }
   }
 
-  // Obtain App ID
-  uint32_t appId = nsIScriptSecurityManager::NO_APP_ID;
   bool     inIsolatedMozBrowser = false;
   const PContentParent *content = Manager()->Manager();
-  if (PBrowserParent* browser = SingleManagedOrNull(content->ManagedPBrowserParent())) {
-    // appId's are for B2G only currently, where managees.Count() == 1
-    // This is not guaranteed currently in Desktop, so skip this there.
-    TabParent *tab = TabParent::GetFrom(browser);
-    appId = tab->OwnAppId();
-    inIsolatedMozBrowser = tab->IsIsolatedMozBrowserElement();
-  }
 
   mSocket = new TCPSocket(nullptr, NS_ConvertUTF8toUTF16(aRemoteHost), aRemotePort, aUseSSL, aUseArrayBuffers);
-  mSocket->SetAppIdAndBrowser(appId, inIsolatedMozBrowser);
+  mSocket->SetAppIdAndBrowser(nsIScriptSecurityManager::NO_APP_ID, inIsolatedMozBrowser);
   mSocket->SetSocketBridgeParent(this);
   rv = mSocket->InitWithUnconnectedTransport(socketTransport);
   NS_ENSURE_SUCCESS(rv, true);
diff --git a/dom/permission/tests/test_embed-apps.html b/dom/permission/tests/test_embed-apps.html
deleted file mode 100644
index 69d4725c79..0000000000
--- a/dom/permission/tests/test_embed-apps.html
+++ /dev/null
@@ -1,61 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=815105
--->
-<head>
-  <meta charset="utf-8">
-  <title>Test for Bug 815105 </title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=815105">Mozilla Bug 815105 </a>
-<p id="display"></p>
-<div id="content" style="display: none"></div>
-<pre id="test">
-<script type="application/javascript;version=1.8" src="file_framework.js"></script>
-<script type="application/javascript;version=1.8">
-/*
- * embed-apps allows us to create app iframes,
- * creator must also have the browser permission
- */
-function verifier(success, failure) {
-  var iframe = document.createElement('iframe');
-  iframe.setAttribute('mozbrowser', '');
-  iframe.setAttribute('mozapp', 'http://example.org/manifest.webapp');
-  iframe.src = "http://example.org/";
-  iframe.addEventListener('load', function() {
-    var appStatus = SpecialPowers.wrap(iframe)
-                                 .contentDocument.nodePrincipal.appStatus;
-
-    if (appStatus != SpecialPowers.Ci
-                                  .nsIPrincipal.APP_STATUS_NOT_INSTALLED) {
-      success("Got mozapp");
-    } else {
-      failure("Didn't get mozapp") ;
-    }
-  });
-
-  document.getElementById('content').appendChild(iframe);
-}
-
-var gData = [
-  {
-    perm: ["embed-apps", "browser"],
-    /*
-     * Android doesn't have working apps
-     * Mobile is for B2G which has a weird testing setup
-     * the app iframe gets embed in the test-container iframe
-     * which returns APP_STATUS_NOT_INSTALLED
-     */
-    skip: ["Android", "Mobile"],
-    settings: [["dom.mozBrowserFramesEnabled", true]],
-    verifier: verifier.toSource(),
-  }
-]
-</script>
-</pre>
-</body>
-</html>
-
diff --git a/dom/quota/ActorsParent.cpp b/dom/quota/ActorsParent.cpp
index c240cbf201..afe93a1f36 100644
--- a/dom/quota/ActorsParent.cpp
+++ b/dom/quota/ActorsParent.cpp
@@ -208,7 +208,6 @@ class DirectoryLockImpl final
   const Nullable<PersistenceType> mPersistenceType;
   const nsCString mGroup;
   const OriginScope mOriginScope;
-  const Nullable<bool> mIsApp;
   const Nullable<Client::Type> mClientType;
   RefPtr<OpenDirectoryListener> mOpenListener;
 
@@ -228,7 +227,6 @@ public:
                     Nullable<PersistenceType> aPersistenceType,
                     const nsACString& aGroup,
                     const OriginScope& aOriginScope,
-                    Nullable<bool> aIsApp,
                     Nullable<Client::Type> aClientType,
                     bool aExclusive,
                     bool aInternal,
@@ -260,12 +258,6 @@ public:
     return mOriginScope;
   }
 
-  const Nullable<bool>&
-  GetIsApp() const
-  {
-    return mIsApp;
-  }
-
   const Nullable<Client::Type>&
   GetClientType() const
   {
@@ -455,10 +447,12 @@ class OriginInfo final
   friend class QuotaObject;
 
 public:
-  OriginInfo(GroupInfo* aGroupInfo, const nsACString& aOrigin, bool aIsApp,
+  OriginInfo(GroupInfo* aGroupInfo, const nsACString& aOrigin,
              uint64_t aUsage, int64_t aAccessTime)
-  : mGroupInfo(aGroupInfo), mOrigin(aOrigin), mUsage(aUsage),
-    mAccessTime(aAccessTime), mIsApp(aIsApp)
+  : mGroupInfo(aGroupInfo)
+  , mOrigin(aOrigin)
+  , mUsage(aUsage)
+  , mAccessTime(aAccessTime)
   {
     MOZ_COUNT_CTOR(OriginInfo);
   }
@@ -497,7 +491,6 @@ private:
   const nsCString mOrigin;
   uint64_t mUsage;
   int64_t mAccessTime;
-  const bool mIsApp;
 };
 
 class OriginInfoLRUComparator
@@ -1024,7 +1017,6 @@ protected:
                     PersistenceType aPersistenceType,
                     const nsACString& aGroup,
                     const nsACString& aOrigin,
-                    bool aIsApp,
                     UsageInfo* aUsageInfo);
 
   // Subclasses use this override to set the IPDL response value.
@@ -1080,7 +1072,6 @@ class GetOriginUsageOp final
   const OriginUsageParams mParams;
   nsCString mSuffix;
   nsCString mGroup;
-  bool mIsApp;
   bool mGetGroupUsage;
 
 public:
@@ -1391,7 +1382,6 @@ struct StorageDirectoryHelper::OriginProps
   nsCString mOrigin;
 
   Type mType;
-  bool mIsApp;
   bool mNeedsRestore;
   bool mIgnore;
 
@@ -1399,7 +1389,6 @@ public:
   explicit OriginProps()
     : mTimestamp(0)
     , mType(eContent)
-    , mIsApp(false)
     , mNeedsRestore(false)
     , mIgnore(false)
   { }
@@ -1567,18 +1556,6 @@ private:
   DoProcessOriginDirectories();
 };
 
-class OriginKey : public nsAutoCString
-{
-public:
-  OriginKey(PersistenceType aPersistenceType,
-            const nsACString& aOrigin)
-  {
-    PersistenceTypeToText(aPersistenceType, *this);
-    Append(':');
-    Append(aOrigin);
-  }
-};
-
 void
 SanitizeOriginString(nsCString& aOrigin)
 {
@@ -1592,25 +1569,6 @@ SanitizeOriginString(nsCString& aOrigin)
   aOrigin.ReplaceChar(QuotaManager::kReplaceChars, '+');
 }
 
-bool
-IsTreatedAsPersistent(PersistenceType aPersistenceType,
-                      bool aIsApp)
-{
-  if (aPersistenceType == PERSISTENCE_TYPE_PERSISTENT ||
-      (aPersistenceType == PERSISTENCE_TYPE_DEFAULT && aIsApp)) {
-    return true;
-  }
-
-  return false;
-}
-
-bool
-IsTreatedAsTemporary(PersistenceType aPersistenceType,
-                     bool aIsApp)
-{
-  return !IsTreatedAsPersistent(aPersistenceType, aIsApp);
-}
-
 nsresult
 CloneStoragePath(nsIFile* aBaseDir,
                  const nsAString& aStorageName,
@@ -1891,9 +1849,11 @@ GetJarPrefix(uint32_t aAppId,
 }
 
 nsresult
-CreateDirectoryMetadata(nsIFile* aDirectory, int64_t aTimestamp,
-                        const nsACString& aSuffix, const nsACString& aGroup,
-                        const nsACString& aOrigin, bool aIsApp)
+CreateDirectoryMetadata(nsIFile* aDirectory,
+                        int64_t aTimestamp,
+                        const nsACString& aSuffix,
+                        const nsACString& aGroup,
+                        const nsACString& aOrigin)
 {
   AssertIsOnIOThread();
 
@@ -1955,7 +1915,8 @@ CreateDirectoryMetadata(nsIFile* aDirectory, int64_t aTimestamp,
     return rv;
   }
 
-  rv = stream->WriteBoolean(aIsApp);
+  // Currently unused (used to be isApp).
+  rv = stream->WriteBoolean(false);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
@@ -1966,7 +1927,7 @@ CreateDirectoryMetadata(nsIFile* aDirectory, int64_t aTimestamp,
 nsresult
 CreateDirectoryMetadata2(nsIFile* aDirectory, int64_t aTimestamp,
                          const nsACString& aSuffix, const nsACString& aGroup,
-                         const nsACString& aOrigin, bool aIsApp)
+                         const nsACString& aOrigin)
 {
   AssertIsOnIOThread();
 
@@ -2019,7 +1980,8 @@ CreateDirectoryMetadata2(nsIFile* aDirectory, int64_t aTimestamp,
     return rv;
   }
 
-  rv = stream->WriteBoolean(aIsApp);
+  // Currently unused (used to be isApp).
+  rv = stream->WriteBoolean(false);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
@@ -2141,7 +2103,6 @@ DirectoryLockImpl::DirectoryLockImpl(QuotaManager* aQuotaManager,
                                      Nullable<PersistenceType> aPersistenceType,
                                      const nsACString& aGroup,
                                      const OriginScope& aOriginScope,
-                                     Nullable<bool> aIsApp,
                                      Nullable<Client::Type> aClientType,
                                      bool aExclusive,
                                      bool aInternal,
@@ -2150,7 +2111,6 @@ DirectoryLockImpl::DirectoryLockImpl(QuotaManager* aQuotaManager,
   , mPersistenceType(aPersistenceType)
   , mGroup(aGroup)
   , mOriginScope(aOriginScope)
-  , mIsApp(aIsApp)
   , mClientType(aClientType)
   , mOpenListener(aOpenListener)
   , mExclusive(aExclusive)
@@ -2165,7 +2125,6 @@ DirectoryLockImpl::DirectoryLockImpl(QuotaManager* aQuotaManager,
                 aPersistenceType.Value() != PERSISTENCE_TYPE_INVALID);
   MOZ_ASSERT_IF(!aInternal, !aGroup.IsEmpty());
   MOZ_ASSERT_IF(!aInternal, aOriginScope.IsOrigin());
-  MOZ_ASSERT_IF(!aInternal, !aIsApp.IsNull());
   MOZ_ASSERT_IF(!aInternal, !aClientType.IsNull());
   MOZ_ASSERT_IF(!aInternal, aClientType.Value() != Client::TYPE_MAX);
   MOZ_ASSERT_IF(!aInternal, aOpenListener);
@@ -2845,7 +2804,6 @@ auto
 QuotaManager::CreateDirectoryLock(Nullable<PersistenceType> aPersistenceType,
                                   const nsACString& aGroup,
                                   const OriginScope& aOriginScope,
-                                  Nullable<bool> aIsApp,
                                   Nullable<Client::Type> aClientType,
                                   bool aExclusive,
                                   bool aInternal,
@@ -2859,7 +2817,6 @@ QuotaManager::CreateDirectoryLock(Nullable<PersistenceType> aPersistenceType,
                 aPersistenceType.Value() != PERSISTENCE_TYPE_INVALID);
   MOZ_ASSERT_IF(!aInternal, !aGroup.IsEmpty());
   MOZ_ASSERT_IF(!aInternal, aOriginScope.IsOrigin());
-  MOZ_ASSERT_IF(!aInternal, !aIsApp.IsNull());
   MOZ_ASSERT_IF(!aInternal, !aClientType.IsNull());
   MOZ_ASSERT_IF(!aInternal, aClientType.Value() != Client::TYPE_MAX);
   MOZ_ASSERT_IF(!aInternal, aOpenListener);
@@ -2868,7 +2825,6 @@ QuotaManager::CreateDirectoryLock(Nullable<PersistenceType> aPersistenceType,
                                                            aPersistenceType,
                                                            aGroup,
                                                            aOriginScope,
-                                                           aIsApp,
                                                            aClientType,
                                                            aExclusive,
                                                            aInternal,
@@ -2900,8 +2856,7 @@ QuotaManager::CreateDirectoryLock(Nullable<PersistenceType> aPersistenceType,
 auto
 QuotaManager::CreateDirectoryLockForEviction(PersistenceType aPersistenceType,
                                              const nsACString& aGroup,
-                                             const nsACString& aOrigin,
-                                             bool aIsApp)
+                                             const nsACString& aOrigin)
   -> already_AddRefed<DirectoryLockImpl>
 {
   AssertIsOnOwningThread();
@@ -2913,7 +2868,6 @@ QuotaManager::CreateDirectoryLockForEviction(PersistenceType aPersistenceType,
                           Nullable<PersistenceType>(aPersistenceType),
                           aGroup,
                           OriginScope::FromOrigin(aOrigin),
-                          Nullable<bool>(aIsApp),
                           Nullable<Client::Type>(),
                           /* aExclusive */ true,
                           /* aInternal */ true,
@@ -3028,8 +2982,7 @@ QuotaManager::CollectOriginsForEviction(
                            nsTArray<OriginInfo*>& aInactiveOriginInfos)
     {
       for (OriginInfo* originInfo : aOriginInfos) {
-        MOZ_ASSERT(IsTreatedAsTemporary(originInfo->mGroupInfo->mPersistenceType,
-                                        originInfo->mIsApp));
+        MOZ_ASSERT(originInfo->mGroupInfo->mPersistenceType != PERSISTENCE_TYPE_PERSISTENT);
 
         OriginScope originScope = OriginScope::FromOrigin(originInfo->mOrigin);
 
@@ -3132,8 +3085,7 @@ QuotaManager::CollectOriginsForEviction(
       RefPtr<DirectoryLockImpl> lock =
         CreateDirectoryLockForEviction(originInfo->mGroupInfo->mPersistenceType,
                                        originInfo->mGroupInfo->mGroup,
-                                       originInfo->mOrigin,
-                                       originInfo->mIsApp);
+                                       originInfo->mOrigin);
       aLocks.AppendElement(lock.forget());
     }
 
@@ -3283,12 +3235,11 @@ void
 QuotaManager::InitQuotaForOrigin(PersistenceType aPersistenceType,
                                  const nsACString& aGroup,
                                  const nsACString& aOrigin,
-                                 bool aIsApp,
                                  uint64_t aUsageBytes,
                                  int64_t aAccessTime)
 {
   AssertIsOnIOThread();
-  MOZ_ASSERT(IsTreatedAsTemporary(aPersistenceType, aIsApp));
+  MOZ_ASSERT(aPersistenceType != PERSISTENCE_TYPE_PERSISTENT);
 
   MutexAutoLock lock(mQuotaMutex);
 
@@ -3306,7 +3257,7 @@ QuotaManager::InitQuotaForOrigin(PersistenceType aPersistenceType,
   }
 
   RefPtr<OriginInfo> originInfo =
-    new OriginInfo(groupInfo, aOrigin, aIsApp, aUsageBytes, aAccessTime);
+    new OriginInfo(groupInfo, aOrigin, aUsageBytes, aAccessTime);
   groupInfo->LockedAddOriginInfo(originInfo);
 }
 
@@ -3555,13 +3506,11 @@ QuotaManager::GetDirectoryMetadata2(nsIFile* aDirectory,
                                     int64_t* aTimestamp,
                                     nsACString& aSuffix,
                                     nsACString& aGroup,
-                                    nsACString& aOrigin,
-                                    bool* aIsApp)
+                                    nsACString& aOrigin)
 {
   MOZ_ASSERT(!NS_IsMainThread());
   MOZ_ASSERT(aDirectory);
   MOZ_ASSERT(aTimestamp);
-  MOZ_ASSERT(aIsApp);
   MOZ_ASSERT(mStorageInitialized);
 
   nsCOMPtr<nsIBinaryInputStream> binaryStream;
@@ -3606,8 +3555,9 @@ QuotaManager::GetDirectoryMetadata2(nsIFile* aDirectory,
   rv = binaryStream->ReadCString(origin);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  bool isApp;
-  rv = binaryStream->ReadBoolean(&isApp);
+  // Currently unused (used to be isApp).
+  bool dummy;
+  rv = binaryStream->ReadBoolean(&dummy);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
@@ -3616,7 +3566,6 @@ QuotaManager::GetDirectoryMetadata2(nsIFile* aDirectory,
   aSuffix = suffix;
   aGroup = group;
   aOrigin = origin;
-  *aIsApp = isApp;
   return NS_OK;
 }
 
@@ -3626,15 +3575,13 @@ QuotaManager::GetDirectoryMetadata2WithRestore(nsIFile* aDirectory,
                                                int64_t* aTimestamp,
                                                nsACString& aSuffix,
                                                nsACString& aGroup,
-                                               nsACString& aOrigin,
-                                               bool* aIsApp)
+                                               nsACString& aOrigin)
 {
   nsresult rv = GetDirectoryMetadata2(aDirectory,
                                       aTimestamp,
                                       aSuffix,
                                       aGroup,
-                                      aOrigin,
-                                      aIsApp);
+                                      aOrigin);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     rv = RestoreDirectoryMetadata2(aDirectory, aPersistent);
     if (NS_WARN_IF(NS_FAILED(rv))) {
@@ -3645,8 +3592,7 @@ QuotaManager::GetDirectoryMetadata2WithRestore(nsIFile* aDirectory,
                                aTimestamp,
                                aSuffix,
                                aGroup,
-                               aOrigin,
-                               aIsApp);
+                               aOrigin);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
@@ -3770,24 +3716,17 @@ QuotaManager::InitializeRepository(PersistenceType aPersistenceType)
     nsCString suffix;
     nsCString group;
     nsCString origin;
-    bool isApp;
     rv = GetDirectoryMetadata2WithRestore(childDirectory,
                                           /* aPersistent */ false,
                                           &timestamp,
                                           suffix,
                                           group,
-                                          origin,
-                                          &isApp);
+                                          origin);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
 
-    if (IsTreatedAsPersistent(aPersistenceType, isApp)) {
-      continue;
-    }
-
-    rv = InitializeOrigin(aPersistenceType, group, origin, isApp, timestamp,
-                          childDirectory);
+    rv = InitializeOrigin(aPersistenceType, group, origin, timestamp, childDirectory);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
@@ -3834,7 +3773,6 @@ nsresult
 QuotaManager::InitializeOrigin(PersistenceType aPersistenceType,
                                const nsACString& aGroup,
                                const nsACString& aOrigin,
-                               bool aIsApp,
                                int64_t aAccessTime,
                                nsIFile* aDirectory)
 {
@@ -3842,7 +3780,7 @@ QuotaManager::InitializeOrigin(PersistenceType aPersistenceType,
 
   nsresult rv;
 
-  bool trackQuota = IsQuotaEnforced(aPersistenceType, aOrigin, aIsApp);
+  bool trackQuota = aPersistenceType != PERSISTENCE_TYPE_PERSISTENT;
 
   // We need to initialize directories of all clients if they exists and also
   // get the total usage to initialize the quota.
@@ -3904,7 +3842,7 @@ QuotaManager::InitializeOrigin(PersistenceType aPersistenceType,
   }
 
   if (trackQuota) {
-    InitQuotaForOrigin(aPersistenceType, aGroup, aOrigin, aIsApp,
+    InitQuotaForOrigin(aPersistenceType, aGroup, aOrigin,
                        usageInfo->TotalUsage(), aAccessTime);
   }
 
@@ -4383,7 +4321,6 @@ void
 QuotaManager::OpenDirectory(PersistenceType aPersistenceType,
                             const nsACString& aGroup,
                             const nsACString& aOrigin,
-                            bool aIsApp,
                             Client::Type aClientType,
                             bool aExclusive,
                             OpenDirectoryListener* aOpenListener)
@@ -4394,7 +4331,6 @@ QuotaManager::OpenDirectory(PersistenceType aPersistenceType,
     CreateDirectoryLock(Nullable<PersistenceType>(aPersistenceType),
                         aGroup,
                         OriginScope::FromOrigin(aOrigin),
-                        Nullable<bool>(aIsApp),
                         Nullable<Client::Type>(aClientType),
                         aExclusive,
                         false,
@@ -4415,7 +4351,6 @@ QuotaManager::OpenDirectoryInternal(Nullable<PersistenceType> aPersistenceType,
     CreateDirectoryLock(aPersistenceType,
                         EmptyCString(),
                         aOriginScope,
-                        Nullable<bool>(),
                         Nullable<Client::Type>(aClientType),
                         aExclusive,
                         true,
@@ -4471,7 +4406,6 @@ QuotaManager::EnsureOriginIsInitialized(PersistenceType aPersistenceType,
                                         const nsACString& aSuffix,
                                         const nsACString& aGroup,
                                         const nsACString& aOrigin,
-                                        bool aIsApp,
                                         nsIFile** aDirectory)
 {
   AssertIsOnIOThread();
@@ -4485,8 +4419,8 @@ QuotaManager::EnsureOriginIsInitialized(PersistenceType aPersistenceType,
                              getter_AddRefs(directory));
   NS_ENSURE_SUCCESS(rv, rv);
 
-  if (IsTreatedAsPersistent(aPersistenceType, aIsApp)) {
-    if (mInitializedOrigins.Contains(OriginKey(aPersistenceType, aOrigin))) {
+  if (aPersistenceType == PERSISTENCE_TYPE_PERSISTENT) {
+    if (mInitializedOrigins.Contains(aOrigin)) {
       directory.forget(aDirectory);
       return NS_OK;
     }
@@ -4538,7 +4472,7 @@ QuotaManager::EnsureOriginIsInitialized(PersistenceType aPersistenceType,
   rv = EnsureDirectory(directory, &created);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  if (IsTreatedAsPersistent(aPersistenceType, aIsApp)) {
+  if (aPersistenceType == PERSISTENCE_TYPE_PERSISTENT) {
     if (created) {
       timestamp = PR_Now();
 
@@ -4546,8 +4480,7 @@ QuotaManager::EnsureOriginIsInitialized(PersistenceType aPersistenceType,
                                    timestamp,
                                    aSuffix,
                                    aGroup,
-                                   aOrigin,
-                                   aIsApp);
+                                   aOrigin);
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return rv;
       }
@@ -4556,13 +4489,11 @@ QuotaManager::EnsureOriginIsInitialized(PersistenceType aPersistenceType,
                                     timestamp,
                                     aSuffix,
                                     aGroup,
-                                    aOrigin,
-                                    aIsApp);
+                                    aOrigin);
       NS_ENSURE_SUCCESS(rv, rv);
     } else {
-      bool persistent = aPersistenceType == PERSISTENCE_TYPE_PERSISTENT;
       rv = GetDirectoryMetadata2WithRestore(directory,
-                                            persistent,
+                                            /* aPersistent */ true,
                                             &timestamp);
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return rv;
@@ -4571,11 +4502,10 @@ QuotaManager::EnsureOriginIsInitialized(PersistenceType aPersistenceType,
       MOZ_ASSERT(timestamp <= PR_Now());
     }
 
-    rv = InitializeOrigin(aPersistenceType, aGroup, aOrigin, aIsApp, timestamp,
-                          directory);
+    rv = InitializeOrigin(aPersistenceType, aGroup, aOrigin, timestamp, directory);
     NS_ENSURE_SUCCESS(rv, rv);
 
-    mInitializedOrigins.AppendElement(OriginKey(aPersistenceType, aOrigin));
+    mInitializedOrigins.AppendElement(aOrigin);
   } else if (created) {
     timestamp = PR_Now();
 
@@ -4583,8 +4513,7 @@ QuotaManager::EnsureOriginIsInitialized(PersistenceType aPersistenceType,
                                  timestamp,
                                  aSuffix,
                                  aGroup,
-                                 aOrigin,
-                                 aIsApp);
+                                 aOrigin);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
@@ -4593,12 +4522,10 @@ QuotaManager::EnsureOriginIsInitialized(PersistenceType aPersistenceType,
                                   timestamp,
                                   aSuffix,
                                   aGroup,
-                                  aOrigin,
-                                  aIsApp);
+                                  aOrigin);
     NS_ENSURE_SUCCESS(rv, rv);
 
-    rv = InitializeOrigin(aPersistenceType, aGroup, aOrigin, aIsApp, timestamp,
-                          directory);
+    rv = InitializeOrigin(aPersistenceType, aGroup, aOrigin, timestamp, directory);
     NS_ENSURE_SUCCESS(rv, rv);
   }
 
@@ -4608,13 +4535,12 @@ QuotaManager::EnsureOriginIsInitialized(PersistenceType aPersistenceType,
 
 void
 QuotaManager::OriginClearCompleted(PersistenceType aPersistenceType,
-                                   const nsACString& aOrigin,
-                                   bool aIsApp)
+                                   const nsACString& aOrigin)
 {
   AssertIsOnIOThread();
 
-  if (IsTreatedAsPersistent(aPersistenceType, aIsApp)) {
-    mInitializedOrigins.RemoveElement(OriginKey(aPersistenceType, aOrigin));
+  if (aPersistenceType == PERSISTENCE_TYPE_PERSISTENT) {
+    mInitializedOrigins.RemoveElement(aOrigin);
   }
 
   for (uint32_t index = 0; index < Client::TYPE_MAX; index++) {
@@ -4715,14 +4641,13 @@ nsresult
 QuotaManager::GetInfoFromPrincipal(nsIPrincipal* aPrincipal,
                                    nsACString* aSuffix,
                                    nsACString* aGroup,
-                                   nsACString* aOrigin,
-                                   bool* aIsApp)
+                                   nsACString* aOrigin)
 {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(aPrincipal);
 
   if (nsContentUtils::IsSystemPrincipal(aPrincipal)) {
-    GetInfoForChrome(aSuffix, aGroup, aOrigin, aIsApp);
+    GetInfoForChrome(aSuffix, aGroup, aOrigin);
     return NS_OK;
   }
 
@@ -4780,11 +4705,6 @@ QuotaManager::GetInfoFromPrincipal(nsIPrincipal* aPrincipal,
     aOrigin->Assign(origin);
   }
 
-  if (aIsApp) {
-    *aIsApp = aPrincipal->GetAppStatus() !=
-                nsIPrincipal::APP_STATUS_NOT_INSTALLED;
-  }
-
   return NS_OK;
 }
 
@@ -4793,8 +4713,7 @@ nsresult
 QuotaManager::GetInfoFromWindow(nsPIDOMWindowOuter* aWindow,
                                 nsACString* aSuffix,
                                 nsACString* aGroup,
-                                nsACString* aOrigin,
-                                bool* aIsApp)
+                                nsACString* aOrigin)
 {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(aWindow);
@@ -4806,7 +4725,7 @@ QuotaManager::GetInfoFromWindow(nsPIDOMWindowOuter* aWindow,
   NS_ENSURE_TRUE(principal, NS_ERROR_FAILURE);
 
   nsresult rv =
-    GetInfoFromPrincipal(principal, aSuffix, aGroup, aOrigin, aIsApp);
+    GetInfoFromPrincipal(principal, aSuffix, aGroup, aOrigin);
   NS_ENSURE_SUCCESS(rv, rv);
 
   return NS_OK;
@@ -4816,8 +4735,7 @@ QuotaManager::GetInfoFromWindow(nsPIDOMWindowOuter* aWindow,
 void
 QuotaManager::GetInfoForChrome(nsACString* aSuffix,
                                nsACString* aGroup,
-                               nsACString* aOrigin,
-                               bool* aIsApp)
+                               nsACString* aOrigin)
 {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(nsContentUtils::LegacyIsCallerChromeOrNativeCode());
@@ -4831,9 +4749,6 @@ QuotaManager::GetInfoForChrome(nsACString* aSuffix,
   if (aOrigin) {
     ChromeOrigin(*aOrigin);
   }
-  if (aIsApp) {
-    *aIsApp = false;
-  }
 }
 
 // static
@@ -4851,28 +4766,6 @@ QuotaManager::IsOriginInternal(const nsACString& aOrigin)
   return false;
 }
 
-// static
-bool
-QuotaManager::IsFirstPromptRequired(PersistenceType aPersistenceType,
-                                    const nsACString& aOrigin,
-                                    bool aIsApp)
-{
-  if (IsTreatedAsTemporary(aPersistenceType, aIsApp)) {
-    return false;
-  }
-
-  return !IsOriginInternal(aOrigin);
-}
-
-// static
-bool
-QuotaManager::IsQuotaEnforced(PersistenceType aPersistenceType,
-                              const nsACString& aOrigin,
-                              bool aIsApp)
-{
-  return IsTreatedAsTemporary(aPersistenceType, aIsApp);
-}
-
 // static
 void
 QuotaManager::ChromeOrigin(nsACString& aOrigin)
@@ -5054,21 +4947,19 @@ QuotaManager::CheckTemporaryStorageLimits()
         doomedOriginInfo->mGroupInfo->mPersistenceType;
       nsCString group = doomedOriginInfo->mGroupInfo->mGroup;
       nsCString origin = doomedOriginInfo->mOrigin;
-      bool isApp = doomedOriginInfo->mIsApp;
       LockedRemoveQuotaForOrigin(persistenceType, group, origin);
 
 #ifdef DEBUG
       doomedOriginInfos[index] = nullptr;
 #endif
 
-      doomedOrigins.AppendElement(OriginParams(persistenceType, origin, isApp));
+      doomedOrigins.AppendElement(OriginParams(persistenceType, origin));
     }
   }
 
   for (const OriginParams& doomedOrigin : doomedOrigins) {
     OriginClearCompleted(doomedOrigin.mPersistenceType,
-                         doomedOrigin.mOrigin,
-                         doomedOrigin.mIsApp);
+                         doomedOrigin.mOrigin);
   }
 }
 
@@ -5546,8 +5437,7 @@ FinalizeOriginEvictionOp::DoDirectoryWork(QuotaManager* aQuotaManager)
 
   for (RefPtr<DirectoryLockImpl>& lock : mLocks) {
     aQuotaManager->OriginClearCompleted(lock->GetPersistenceType().Value(),
-                                        lock->GetOriginScope().GetOrigin(),
-                                        lock->GetIsApp().Value());
+                                        lock->GetOriginScope().GetOrigin());
   }
 
   return NS_OK;
@@ -5916,7 +5806,6 @@ QuotaUsageRequestBase::GetUsageForOrigin(QuotaManager* aQuotaManager,
                                          PersistenceType aPersistenceType,
                                          const nsACString& aGroup,
                                          const nsACString& aOrigin,
-                                         bool aIsApp,
                                          UsageInfo* aUsageInfo)
 {
   AssertIsOnIOThread();
@@ -5939,9 +5828,8 @@ QuotaUsageRequestBase::GetUsageForOrigin(QuotaManager* aQuotaManager,
   if (exists && !mCanceled) {
     bool initialized;
 
-    if (IsTreatedAsPersistent(aPersistenceType, aIsApp)) {
-      nsCString originKey = OriginKey(aPersistenceType, aOrigin);
-      initialized = aQuotaManager->IsOriginInitialized(originKey);
+    if (aPersistenceType == PERSISTENCE_TYPE_PERSISTENT) {
+      initialized = aQuotaManager->IsOriginInitialized(mOriginScope.GetOrigin());
     } else {
       initialized = aQuotaManager->IsTemporaryStorageInitialized();
     }
@@ -6147,14 +6035,12 @@ GetUsageOp::TraverseRepository(QuotaManager* aQuotaManager,
     nsCString suffix;
     nsCString group;
     nsCString origin;
-    bool isApp;
     rv = aQuotaManager->GetDirectoryMetadata2WithRestore(originDir,
                                                          persistent,
                                                          &timestamp,
                                                          suffix,
                                                          group,
-                                                         origin,
-                                                         &isApp);
+                                                         origin);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
@@ -6188,7 +6074,6 @@ GetUsageOp::TraverseRepository(QuotaManager* aQuotaManager,
                            aPersistenceType,
                            group,
                            origin,
-                           isApp,
                            &usageInfo);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
@@ -6279,8 +6164,7 @@ GetOriginUsageOp::DoInitOnMainThread()
 
   // Figure out which origin we're dealing with.
   nsCString origin;
-  rv = QuotaManager::GetInfoFromPrincipal(principal, &mSuffix, &mGroup,
-                                          &origin, &mIsApp);
+  rv = QuotaManager::GetInfoFromPrincipal(principal, &mSuffix, &mGroup, &origin);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
@@ -6309,7 +6193,6 @@ GetOriginUsageOp::DoDirectoryWork(QuotaManager* aQuotaManager)
     rv = aQuotaManager->EnsureOriginIsInitialized(PERSISTENCE_TYPE_TEMPORARY,
                                                   mSuffix, mGroup,
                                                   mOriginScope.GetOrigin(),
-                                                  mIsApp,
                                                   getter_AddRefs(directory));
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
@@ -6328,7 +6211,6 @@ GetOriginUsageOp::DoDirectoryWork(QuotaManager* aQuotaManager)
                            type,
                            mGroup,
                            mOriginScope.GetOrigin(),
-                           mIsApp,
                            &usageInfo);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
@@ -6542,8 +6424,7 @@ OriginClearOp::DoInitOnMainThread()
 
     // Figure out which origin we're dealing with.
     nsCString origin;
-    rv = QuotaManager::GetInfoFromPrincipal(principal, nullptr, nullptr, &origin,
-                                            nullptr);
+    rv = QuotaManager::GetInfoFromPrincipal(principal, nullptr, nullptr, &origin);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
@@ -6637,14 +6518,12 @@ OriginClearOp::DeleteFiles(QuotaManager* aQuotaManager,
     nsCString suffix;
     nsCString group;
     nsCString origin;
-    bool isApp;
     rv = aQuotaManager->GetDirectoryMetadata2WithRestore(file,
                                                          persistent,
                                                          &timestamp,
                                                          suffix,
                                                          group,
-                                                         origin,
-                                                         &isApp);
+                                                         origin);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return;
     }
@@ -6668,7 +6547,7 @@ OriginClearOp::DeleteFiles(QuotaManager* aQuotaManager,
       aQuotaManager->RemoveQuotaForOrigin(aPersistenceType, group, origin);
     }
 
-    aQuotaManager->OriginClearCompleted(aPersistenceType, origin, isApp);
+    aQuotaManager->OriginClearCompleted(aPersistenceType, origin);
   }
 
 }
@@ -6803,8 +6682,7 @@ StorageDirectoryHelper::RunOnMainThread()
       case OriginProps::eChrome: {
         QuotaManager::GetInfoForChrome(&originProps.mSuffix,
                                        &originProps.mGroup,
-                                       &originProps.mOrigin,
-                                       &originProps.mIsApp);
+                                       &originProps.mOrigin);
         break;
       }
 
@@ -6824,8 +6702,7 @@ StorageDirectoryHelper::RunOnMainThread()
         rv = QuotaManager::GetInfoFromPrincipal(principal,
                                                 &originProps.mSuffix,
                                                 &originProps.mGroup,
-                                                &originProps.mOrigin,
-                                                &originProps.mIsApp);
+                                                &originProps.mOrigin);
         if (NS_WARN_IF(NS_FAILED(rv))) {
           return rv;
         }
@@ -7544,8 +7421,7 @@ CreateOrUpgradeDirectoryMetadataHelper::DoProcessOriginDirectories()
                                    originProps.mTimestamp,
                                    originProps.mSuffix,
                                    originProps.mGroup,
-                                   originProps.mOrigin,
-                                   originProps.mIsApp);
+                                   originProps.mOrigin);
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return rv;
       }
@@ -7611,8 +7487,7 @@ CreateOrUpgradeDirectoryMetadataHelper::DoProcessOriginDirectories()
                                    originProps.mTimestamp,
                                    originProps.mSuffix,
                                    originProps.mGroup,
-                                   originProps.mOrigin,
-                                   originProps.mIsApp);
+                                   originProps.mOrigin);
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return rv;
       }
@@ -7628,7 +7503,8 @@ CreateOrUpgradeDirectoryMetadataHelper::DoProcessOriginDirectories()
 
       MOZ_ASSERT(stream);
 
-      rv = stream->WriteBoolean(originProps.mIsApp);
+      // Currently unused (used to be isApp).
+      rv = stream->WriteBoolean(false);
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return rv;
       }
@@ -7801,8 +7677,7 @@ UpgradeDirectoryMetadataFrom1To2Helper::DoProcessOriginDirectories()
                                    originProps.mTimestamp,
                                    originProps.mSuffix,
                                    originProps.mGroup,
-                                   originProps.mOrigin,
-                                   originProps.mIsApp);
+                                   originProps.mOrigin);
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return rv;
       }
@@ -7812,8 +7687,7 @@ UpgradeDirectoryMetadataFrom1To2Helper::DoProcessOriginDirectories()
                                   originProps.mTimestamp,
                                   originProps.mSuffix,
                                   originProps.mGroup,
-                                  originProps.mOrigin,
-                                  originProps.mIsApp);
+                                  originProps.mOrigin);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
@@ -7883,8 +7757,7 @@ RestoreDirectoryMetadata2Helper::DoProcessOriginDirectories()
                                          originProps.mTimestamp,
                                          originProps.mSuffix,
                                          originProps.mGroup,
-                                         originProps.mOrigin,
-                                         originProps.mIsApp);
+                                         originProps.mOrigin);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
diff --git a/dom/quota/QuotaManager.h b/dom/quota/QuotaManager.h
index 06a54f761f..20b9831d87 100644
--- a/dom/quota/QuotaManager.h
+++ b/dom/quota/QuotaManager.h
@@ -81,16 +81,13 @@ protected:
 struct OriginParams
 {
   OriginParams(PersistenceType aPersistenceType,
-               const nsACString& aOrigin,
-               bool aIsApp)
+               const nsACString& aOrigin)
   : mOrigin(aOrigin)
   , mPersistenceType(aPersistenceType)
-  , mIsApp(aIsApp)
   { }
 
   nsCString mOrigin;
   PersistenceType mPersistenceType;
-  bool mIsApp;
 };
 
 class QuotaManager final
@@ -152,7 +149,6 @@ public:
   InitQuotaForOrigin(PersistenceType aPersistenceType,
                      const nsACString& aGroup,
                      const nsACString& aOrigin,
-                     bool aIsApp,
                      uint64_t aUsageBytes,
                      int64_t aAccessTime);
 
@@ -209,8 +205,7 @@ public:
                         int64_t* aTimestamp,
                         nsACString& aSuffix,
                         nsACString& aGroup,
-                        nsACString& aOrigin,
-                        bool* aIsApp);
+                        nsACString& aOrigin);
 
   nsresult
   GetDirectoryMetadata2WithRestore(nsIFile* aDirectory,
@@ -218,8 +213,7 @@ public:
                                    int64_t* aTimestamp,
                                    nsACString& aSuffix,
                                    nsACString& aGroup,
-                                   nsACString& aOrigin,
-                                   bool* aIsApp);
+                                   nsACString& aOrigin);
 
   nsresult
   GetDirectoryMetadata2(nsIFile* aDirectory, int64_t* aTimestamp);
@@ -248,7 +242,6 @@ public:
   OpenDirectory(PersistenceType aPersistenceType,
                 const nsACString& aGroup,
                 const nsACString& aOrigin,
-                bool aIsApp,
                 Client::Type aClientType,
                 bool aExclusive,
                 OpenDirectoryListener* aOpenListener);
@@ -274,13 +267,11 @@ public:
                             const nsACString& aSuffix,
                             const nsACString& aGroup,
                             const nsACString& aOrigin,
-                            bool aIsApp,
                             nsIFile** aDirectory);
 
   void
   OriginClearCompleted(PersistenceType aPersistenceType,
-                       const nsACString& aOrigin,
-                       bool aIsApp);
+                       const nsACString& aOrigin);
 
   void
   ResetOrClearCompleted();
@@ -366,35 +357,22 @@ public:
   GetInfoFromPrincipal(nsIPrincipal* aPrincipal,
                        nsACString* aSuffix,
                        nsACString* aGroup,
-                       nsACString* aOrigin,
-                       bool* aIsApp);
+                       nsACString* aOrigin);
 
   static nsresult
   GetInfoFromWindow(nsPIDOMWindowOuter* aWindow,
                     nsACString* aSuffix,
                     nsACString* aGroup,
-                    nsACString* aOrigin,
-                    bool* aIsApp);
+                    nsACString* aOrigin);
 
   static void
   GetInfoForChrome(nsACString* aSuffix,
                    nsACString* aGroup,
-                   nsACString* aOrigin,
-                   bool* aIsApp);
+                   nsACString* aOrigin);
 
   static bool
   IsOriginInternal(const nsACString& aOrigin);
 
-  static bool
-  IsFirstPromptRequired(PersistenceType aPersistenceType,
-                        const nsACString& aOrigin,
-                        bool aIsApp);
-
-  static bool
-  IsQuotaEnforced(PersistenceType aPersistenceType,
-                  const nsACString& aOrigin,
-                  bool aIsApp);
-
   static void
   ChromeOrigin(nsACString& aOrigin);
 
@@ -413,7 +391,6 @@ private:
   CreateDirectoryLock(Nullable<PersistenceType> aPersistenceType,
                       const nsACString& aGroup,
                       const OriginScope& aOriginScope,
-                      Nullable<bool> aIsApp,
                       Nullable<Client::Type> aClientType,
                       bool aExclusive,
                       bool aInternal,
@@ -422,8 +399,7 @@ private:
   already_AddRefed<DirectoryLockImpl>
   CreateDirectoryLockForEviction(PersistenceType aPersistenceType,
                                  const nsACString& aGroup,
-                                 const nsACString& aOrigin,
-                                 bool aIsApp);
+                                 const nsACString& aOrigin);
 
   void
   RegisterDirectoryLock(DirectoryLockImpl* aLock);
@@ -468,7 +444,6 @@ private:
   InitializeOrigin(PersistenceType aPersistenceType,
                    const nsACString& aGroup,
                    const nsACString& aOrigin,
-                   bool aIsApp,
                    int64_t aAccessTime,
                    nsIFile* aDirectory);
 
diff --git a/dom/webidl/HTMLIFrameElement.webidl b/dom/webidl/HTMLIFrameElement.webidl
index d2859c6dbc..248e9c7fee 100644
--- a/dom/webidl/HTMLIFrameElement.webidl
+++ b/dom/webidl/HTMLIFrameElement.webidl
@@ -63,11 +63,5 @@ partial interface HTMLIFrameElement {
            attribute boolean mozbrowser;
 };
 
-partial interface HTMLIFrameElement {
-  // nsIMozBrowserFrame
-  [ChromeOnly]
-  readonly attribute DOMString appManifestURL;
-};
-
 HTMLIFrameElement implements MozFrameLoaderOwner;
 HTMLIFrameElement implements BrowserElement;
diff --git a/dom/workers/RuntimeService.cpp b/dom/workers/RuntimeService.cpp
index 0309a67375..62a582e734 100644
--- a/dom/workers/RuntimeService.cpp
+++ b/dom/workers/RuntimeService.cpp
@@ -677,7 +677,6 @@ AsmJSCacheOpenEntryForRead(JS::Handle<JSObject*> aGlobal,
 
 static JS::AsmJSCacheResult
 AsmJSCacheOpenEntryForWrite(JS::Handle<JSObject*> aGlobal,
-                            bool aInstalled,
                             const char16_t* aBegin,
                             const char16_t* aEnd,
                             size_t aSize,
@@ -689,8 +688,7 @@ AsmJSCacheOpenEntryForWrite(JS::Handle<JSObject*> aGlobal,
     return JS::AsmJSCache_InternalError;
   }
 
-  return asmjscache::OpenEntryForWrite(principal, aInstalled, aBegin, aEnd,
-                                       aSize, aMemory, aHandle);
+  return asmjscache::OpenEntryForWrite(principal, aBegin, aEnd, aSize, aMemory, aHandle);
 }
 
 class AsyncTaskWorkerHolder final : public WorkerHolder
diff --git a/dom/workers/ServiceWorkerManager.h b/dom/workers/ServiceWorkerManager.h
index bbf185ff81..8d2600ea48 100644
--- a/dom/workers/ServiceWorkerManager.h
+++ b/dom/workers/ServiceWorkerManager.h
@@ -32,7 +32,6 @@
 #include "nsTArrayForwardDeclare.h"
 #include "nsTObserverArray.h"
 
-class mozIApplicationClearPrivateDataParams;
 class nsIConsoleReportCollector;
 
 namespace mozilla {
diff --git a/dom/xul/nsXULElement.cpp b/dom/xul/nsXULElement.cpp
index 96e6cc516f..961de20ee3 100644
--- a/dom/xul/nsXULElement.cpp
+++ b/dom/xul/nsXULElement.cpp
@@ -1619,17 +1619,6 @@ nsXULElement::GetFrameLoader()
     return already_AddRefed<nsFrameLoader>(static_cast<nsFrameLoader*>(loader.forget().take()));
 }
 
-nsresult
-nsXULElement::GetParentApplication(mozIApplication** aApplication)
-{
-    if (!aApplication) {
-        return NS_ERROR_FAILURE;
-    }
-
-    *aApplication = nullptr;
-    return NS_OK;
-}
-
 void
 nsXULElement::PresetOpenerWindow(mozIDOMWindowProxy* aWindow, ErrorResult& aRv)
 {
diff --git a/dom/xul/nsXULElement.h b/dom/xul/nsXULElement.h
index a307141452..87e0dd3144 100644
--- a/dom/xul/nsXULElement.h
+++ b/dom/xul/nsXULElement.h
@@ -412,7 +412,6 @@ public:
     virtual mozilla::EventStates IntrinsicState() const override;
 
     nsresult GetFrameLoaderXPCOM(nsIFrameLoader** aFrameLoader);
-    nsresult GetParentApplication(mozIApplication** aApplication);
     void PresetOpenerWindow(mozIDOMWindowProxy* aWindow, ErrorResult& aRv);
     nsresult SetIsPrerendered();
 
diff --git a/embedding/components/windowwatcher/nsWindowWatcher.cpp b/embedding/components/windowwatcher/nsWindowWatcher.cpp
index 7839228cfc..aa4d5e3914 100644
--- a/embedding/components/windowwatcher/nsWindowWatcher.cpp
+++ b/embedding/components/windowwatcher/nsWindowWatcher.cpp
@@ -1982,7 +1982,7 @@ nsWindowWatcher::CalculateChromeFlagsForParent(mozIDOMWindowProxy* aParent,
   // Disable CHROME_OPENAS_DIALOG if the window is inside <iframe mozbrowser>.
   // It's up to the embedder to interpret what dialog=1 means.
   nsCOMPtr<nsIDocShell> docshell = do_GetInterface(aParent);
-  if (docshell && docshell->GetIsInMozBrowserOrApp()) {
+  if (docshell && docshell->GetIsInMozBrowser()) {
     chromeFlags &= ~nsIWebBrowserChrome::CHROME_OPENAS_DIALOG;
   }
 
diff --git a/extensions/cookie/nsPermissionManager.cpp b/extensions/cookie/nsPermissionManager.cpp
index afdaea63f1..f8fa542e76 100644
--- a/extensions/cookie/nsPermissionManager.cpp
+++ b/extensions/cookie/nsPermissionManager.cpp
@@ -29,8 +29,6 @@
 #include "nsIPrincipal.h"
 #include "nsContentUtils.h"
 #include "nsIScriptSecurityManager.h"
-#include "nsIAppsService.h"
-#include "mozIApplication.h"
 #include "nsIEffectiveTLDService.h"
 #include "nsPIDOMWindow.h"
 #include "nsIDocument.h"
@@ -1531,12 +1529,6 @@ nsPermissionManager::AddInternal(nsIPrincipal* aPrincipal,
     ContentParent::GetAll(cplist);
     for (uint32_t i = 0; i < cplist.Length(); ++i) {
       ContentParent* cp = cplist[i];
-      // On platforms where we use a preallocated template process we don't
-      // want to notify this process about session specific permissions so
-      // new tabs or apps created on it won't inherit the session permissions.
-      if (cp->IsPreallocated() &&
-          aExpireType == nsIPermissionManager::EXPIRE_SESSION)
-        continue;
       if (cp->NeedsPermissionsUpdate())
         Unused << cp->SendAddPermission(permission);
     }
diff --git a/gfx/thebes/gfxPrefs.h b/gfx/thebes/gfxPrefs.h
index 382cc0ee20..e24e7eb037 100644
--- a/gfx/thebes/gfxPrefs.h
+++ b/gfx/thebes/gfxPrefs.h
@@ -446,7 +446,6 @@ private:
   DECL_GFX_PREF(Once, "image.mem.surfacecache.max_size_kb",    ImageMemSurfaceCacheMaxSizeKB, uint32_t, 100 * 1024);
   DECL_GFX_PREF(Once, "image.mem.surfacecache.min_expiration_ms", ImageMemSurfaceCacheMinExpirationMS, uint32_t, 60*1000);
   DECL_GFX_PREF(Once, "image.mem.surfacecache.size_factor",    ImageMemSurfaceCacheSizeFactor, uint32_t, 64);
-  DECL_GFX_PREF(Live, "image.mozsamplesize.enabled",           ImageMozSampleSizeEnabled, bool, false);
   DECL_GFX_PREF(Once, "image.multithreaded_decoding.limit",    ImageMTDecodingLimit, int32_t, -1);
   DECL_GFX_PREF(Live, "image.webp.enabled",                    ImageWebPEnabled, bool, true);
 #ifdef MOZ_JXL
diff --git a/hal/Hal.cpp b/hal/Hal.cpp
index 88c1fa50bb..4baf617217 100644
--- a/hal/Hal.cpp
+++ b/hal/Hal.cpp
@@ -684,8 +684,6 @@ ProcessPriorityToString(ProcessPriority aPriority)
   switch (aPriority) {
   case PROCESS_PRIORITY_MASTER:
     return "MASTER";
-  case PROCESS_PRIORITY_PREALLOC:
-    return "PREALLOC";
   case PROCESS_PRIORITY_FOREGROUND_HIGH:
     return "FOREGROUND_HIGH";
   case PROCESS_PRIORITY_FOREGROUND:
diff --git a/hal/HalTypes.h b/hal/HalTypes.h
index dc29f0553b..99d295f3f5 100644
--- a/hal/HalTypes.h
+++ b/hal/HalTypes.h
@@ -40,9 +40,6 @@ enum ProcessPriority {
   PROCESS_PRIORITY_BACKGROUND,
   PROCESS_PRIORITY_BACKGROUND_PERCEIVABLE,
   PROCESS_PRIORITY_FOREGROUND_KEYBOARD,
-  // The special class for the preallocated process, high memory priority but
-  // low CPU priority.
-  PROCESS_PRIORITY_PREALLOC,
   // Any priority greater than or equal to FOREGROUND is considered
   // "foreground" for the purposes of priority testing, for example
   // CurrentProcessIsForeground().
diff --git a/image/Decoder.h b/image/Decoder.h
index 87dfb00508..a306cfce37 100644
--- a/image/Decoder.h
+++ b/image/Decoder.h
@@ -179,14 +179,6 @@ public:
    */
   Maybe<gfx::IntSize> ExplicitOutputSize() const;
 
-  /**
-   * Set the requested sample size for this decoder. Used to implement the
-   * -moz-sample-size media fragment.
-   *
-   *  XXX(seth): Support for -moz-sample-size will be removed in bug 1120056.
-   */
-  virtual void SetSampleSize(int aSampleSize) { }
-
   /**
    * Set an iterator to the SourceBuffer which will feed data to this decoder.
    * This must always be called before calling Init(). (And only before Init().)
diff --git a/image/DecoderFactory.cpp b/image/DecoderFactory.cpp
index 916971ba6d..d68f6bd976 100644
--- a/image/DecoderFactory.cpp
+++ b/image/DecoderFactory.cpp
@@ -144,8 +144,7 @@ DecoderFactory::CreateDecoder(DecoderType aType,
                               const IntSize& aIntrinsicSize,
                               const IntSize& aOutputSize,
                               DecoderFlags aDecoderFlags,
-                              SurfaceFlags aSurfaceFlags,
-                              int aSampleSize)
+                              SurfaceFlags aSurfaceFlags)
 {
   if (aType == DecoderType::UNKNOWN) {
     return nullptr;
@@ -163,7 +162,6 @@ DecoderFactory::CreateDecoder(DecoderType aType,
   decoder->SetOutputSize(aOutputSize);
   decoder->SetDecoderFlags(aDecoderFlags | DecoderFlags::FIRST_FRAME_ONLY);
   decoder->SetSurfaceFlags(aSurfaceFlags);
-  decoder->SetSampleSize(aSampleSize);
 
   if (NS_FAILED(decoder->Init())) {
     return nullptr;
@@ -275,8 +273,7 @@ DecoderFactory::CloneAnimationDecoder(Decoder* aDecoder)
 /* static */ already_AddRefed<IDecodingTask>
 DecoderFactory::CreateMetadataDecoder(DecoderType aType,
                                       NotNull<RasterImage*> aImage,
-                                      NotNull<SourceBuffer*> aSourceBuffer,
-                                      int aSampleSize)
+                                      NotNull<SourceBuffer*> aSourceBuffer)
 {
   if (aType == DecoderType::UNKNOWN) {
     return nullptr;
@@ -289,7 +286,6 @@ DecoderFactory::CreateMetadataDecoder(DecoderType aType,
   // Initialize the decoder.
   decoder->SetMetadataDecode(true);
   decoder->SetIterator(aSourceBuffer->Iterator());
-  decoder->SetSampleSize(aSampleSize);
 
   if (NS_FAILED(decoder->Init())) {
     return nullptr;
diff --git a/image/DecoderFactory.h b/image/DecoderFactory.h
index 4267b1f809..900f69f5c4 100644
--- a/image/DecoderFactory.h
+++ b/image/DecoderFactory.h
@@ -66,8 +66,6 @@ public:
    * @param aDecoderFlags Flags specifying the behavior of this decoder.
    * @param aSurfaceFlags Flags specifying the type of output this decoder
    *                      should produce.
-   * @param aSampleSize The sample size requested using #-moz-samplesize (or 0
-   *                    if none).
    */
   static already_AddRefed<IDecodingTask>
   CreateDecoder(DecoderType aType,
@@ -76,8 +74,7 @@ public:
                 const gfx::IntSize& aIntrinsicSize,
                 const gfx::IntSize& aOutputSize,
                 DecoderFlags aDecoderFlags,
-                SurfaceFlags aSurfaceFlags,
-                int aSampleSize);
+                SurfaceFlags aSurfaceFlags);
 
   /**
    * Creates and initializes a decoder for animated images of type @aType.
@@ -124,14 +121,11 @@ public:
    *               notifications as decoding progresses.
    * @param aSourceBuffer The SourceBuffer which the decoder will read its data
    *                      from.
-   * @param aSampleSize The sample size requested using #-moz-samplesize (or 0
-   *                    if none).
    */
   static already_AddRefed<IDecodingTask>
   CreateMetadataDecoder(DecoderType aType,
                         NotNull<RasterImage*> aImage,
-                        NotNull<SourceBuffer*> aSourceBuffer,
-                        int aSampleSize);
+                        NotNull<SourceBuffer*> aSourceBuffer);
 
   /**
    * Creates and initializes a decoder for an ICO resource, which may be either
diff --git a/image/ImageFactory.cpp b/image/ImageFactory.cpp
index 343f7b582b..ccdfe5b96a 100644
--- a/image/ImageFactory.cpp
+++ b/image/ImageFactory.cpp
@@ -230,25 +230,6 @@ ImageFactory::CreateRasterImage(nsIRequest* aRequest,
   aProgressTracker->SetImage(newImage);
   newImage->SetProgressTracker(aProgressTracker);
 
-  nsAutoCString ref;
-  aURI->GetRef(ref);
-  net::nsMediaFragmentURIParser parser(ref);
-  if (parser.HasSampleSize()) {
-      /* Get our principal */
-      nsCOMPtr<nsIChannel> chan(do_QueryInterface(aRequest));
-      nsCOMPtr<nsIPrincipal> principal;
-      if (chan) {
-        nsContentUtils::GetSecurityManager()
-          ->GetChannelResultPrincipal(chan, getter_AddRefs(principal));
-      }
-
-      if ((principal &&
-           principal->GetAppStatus() == nsIPrincipal::APP_STATUS_CERTIFIED) ||
-          gfxPrefs::ImageMozSampleSizeEnabled()) {
-        newImage->SetRequestedSampleSize(parser.GetSampleSize());
-      }
-  }
-
   rv = newImage->Init(aMimeType.get(), aImageFlags);
   if (NS_FAILED(rv)) {
     return BadImage("RasterImage::Init failed", newImage);
diff --git a/image/RasterImage.cpp b/image/RasterImage.cpp
index bb591920ef..31a6d7a991 100644
--- a/image/RasterImage.cpp
+++ b/image/RasterImage.cpp
@@ -72,7 +72,6 @@ RasterImage::RasterImage(ImageURL* aURI /* = nullptr */) :
   mSize(0,0),
   mLockCount(0),
   mDecodeCount(0),
-  mRequestedSampleSize(0),
   mImageProducerID(ImageContainer::AllocateProducerID()),
   mLastFrameID(0),
   mLastImageContainerDrawResult(DrawResult::NOT_READY),
@@ -1200,8 +1199,7 @@ RasterImage::Decode(const IntSize& aSize,
   } else {
     task = DecoderFactory::CreateDecoder(mDecoderType, WrapNotNull(this),
                                          mSourceBuffer, mSize, aSize,
-                                         decoderFlags, surfaceFlags,
-                                         mRequestedSampleSize);
+                                         decoderFlags, surfaceFlags);
   }
 
   // Make sure DecoderFactory was able to create a decoder successfully.
@@ -1228,7 +1226,7 @@ RasterImage::DecodeMetadata(uint32_t aFlags)
   // Create a decoder.
   RefPtr<IDecodingTask> task =
     DecoderFactory::CreateMetadataDecoder(mDecoderType, WrapNotNull(this),
-                                          mSourceBuffer, mRequestedSampleSize);
+                                          mSourceBuffer);
 
   // Make sure DecoderFactory was able to create a decoder successfully.
   if (!task) {
diff --git a/image/RasterImage.h b/image/RasterImage.h
index 42af0a4887..e1a7cb1506 100644
--- a/image/RasterImage.h
+++ b/image/RasterImage.h
@@ -261,11 +261,6 @@ public:
    */
   nsresult SetSourceSizeHint(uint32_t aSizeHint);
 
-  /* Provide a hint for the requested dimension of the resulting image. */
-  void SetRequestedSampleSize(int requestedSampleSize) {
-    mRequestedSampleSize = requestedSampleSize;
-  }
-
  nsCString GetURIString() {
     nsCString spec;
     if (GetURI()) {
@@ -407,9 +402,6 @@ private: // data
   // This is currently only used for statistics
   int32_t                        mDecodeCount;
 
-  // A hint for image decoder that directly scale the image to smaller buffer
-  int                        mRequestedSampleSize;
-
   // A weak pointer to our ImageContainer, which stays alive only as long as
   // the layer system needs it.
   WeakPtr<layers::ImageContainer> mImageContainer;
diff --git a/image/decoders/nsJPEGDecoder.cpp b/image/decoders/nsJPEGDecoder.cpp
index 1ac25fc6e2..c9df02551b 100644
--- a/image/decoders/nsJPEGDecoder.cpp
+++ b/image/decoders/nsJPEGDecoder.cpp
@@ -76,7 +76,6 @@ nsJPEGDecoder::nsJPEGDecoder(RasterImage* aImage,
                                    SIZE_MAX),
           Transition::TerminateSuccess())
  , mDecodeStyle(aDecodeStyle)
- , mSampleSize(0)
 {
   mState = JPEG_HEADER;
   mReading = true;
@@ -239,17 +238,8 @@ nsJPEGDecoder::ReadJPEGData(const char* aData, size_t aLength)
         return Transition::ContinueUnbuffered(State::JPEG_DATA); // I/O suspension
       }
 
-      // If we have a sample size specified for -moz-sample-size, use it.
-      if (mSampleSize > 0) {
-        mInfo.scale_num = 1;
-        mInfo.scale_denom = mSampleSize;
-      }
-
-      // Used to set up image size so arrays can be allocated
-      jpeg_calc_output_dimensions(&mInfo);
-
       // Post our size to the superclass
-      PostSize(mInfo.output_width, mInfo.output_height,
+      PostSize(mInfo.image_width, mInfo.image_height,
                ReadOrientationFromEXIF());
       if (HasError()) {
         // Setting the size led to an error.
@@ -384,6 +374,9 @@ nsJPEGDecoder::ReadJPEGData(const char* aData, size_t aLength)
     mInfo.buffered_image = mDecodeStyle == PROGRESSIVE &&
                            jpeg_has_multiple_scans(&mInfo);
 
+    /* Used to set up image size so arrays can be allocated */
+    jpeg_calc_output_dimensions(&mInfo);
+
     MOZ_ASSERT(!mImageData, "Already have a buffer allocated?");
     nsresult rv = AllocateFrame(OutputSize(), FullOutputFrame(),
                                 SurfaceFormat::B8G8R8X8);
@@ -409,7 +402,7 @@ nsJPEGDecoder::ReadJPEGData(const char* aData, size_t aLength)
     MOZ_LOG(sJPEGDecoderAccountingLog, LogLevel::Debug,
            ("        JPEGDecoderAccounting: nsJPEGDecoder::"
             "Write -- created image frame with %ux%u pixels",
-            mInfo.output_width, mInfo.output_height));
+            mInfo.image_width, mInfo.image_height));
 
     mState = JPEG_START_DECOMPRESS;
     MOZ_FALLTHROUGH; // to start decompressing.
diff --git a/image/decoders/nsJPEGDecoder.h b/image/decoders/nsJPEGDecoder.h
index 25177cef91..14a4ed5646 100644
--- a/image/decoders/nsJPEGDecoder.h
+++ b/image/decoders/nsJPEGDecoder.h
@@ -54,11 +54,6 @@ public:
 
   DecoderType GetType() const override { return DecoderType::JPEG; }
 
-  virtual void SetSampleSize(int aSampleSize) override
-  {
-    mSampleSize = aSampleSize;
-  }
-
   void NotifyDone();
 
 protected:
@@ -115,8 +110,6 @@ public:
   const Decoder::DecodeStyle mDecodeStyle;
 
   uint32_t mCMSMode;
-
-  int mSampleSize;
 };
 
 } // namespace image
diff --git a/image/test/reftest/blob/blob-uri-with-ref-param-notref.html b/image/test/reftest/blob/blob-uri-with-ref-param-notref.html
deleted file mode 100644
index 3b62a3c139..0000000000
--- a/image/test/reftest/blob/blob-uri-with-ref-param-notref.html
+++ /dev/null
@@ -1,41 +0,0 @@
-<!DOCTYPE html>
-
-<html class="reftest-wait">
-
-<body>
-  <img id="test">
-</body>
-
-<script>
-  var image = new Image;
-
-  image.onload = function() {
-    // Create a canvas.
-    var canvas = document.createElement('canvas');
-    canvas.width = 100;
-    canvas.height = 100;
-
-    // Draw the image into the canvas.
-    var ctx = canvas.getContext('2d');
-    ctx.drawImage(image, 0, 0);
-
-    // Convert the image into a blob URI and use it as #test's src.
-    canvas.toBlob(function(blob) {
-      var uri = window.URL.createObjectURL(blob);
-      uri += '#-moz-samplesize=8';
-      var testImage = document.getElementById('test');
-
-      testImage.onload = testImage.onerror = function() {
-        // Take the snapshot.
-        document.documentElement.removeAttribute('class');
-      };
-
-      testImage.src = uri;
-    }, 'image/jpeg', 0.99);
-  }
-
-  // Start loading the image.
-  image.src = 'image.png';
-</script>
-
-</html>
diff --git a/image/test/reftest/blob/blob-uri-with-ref-param.html b/image/test/reftest/blob/blob-uri-with-ref-param.html
deleted file mode 100644
index 8f2e4e7cfd..0000000000
--- a/image/test/reftest/blob/blob-uri-with-ref-param.html
+++ /dev/null
@@ -1,40 +0,0 @@
-<!DOCTYPE html>
-
-<html class="reftest-wait">
-
-<body>
-  <img id="test">
-</body>
-
-<script>
-  var image = new Image;
-
-  image.onload = function() {
-    // Create a canvas.
-    var canvas = document.createElement('canvas');
-    canvas.width = 100;
-    canvas.height = 100;
-
-    // Draw the image into the canvas.
-    var ctx = canvas.getContext('2d');
-    ctx.drawImage(image, 0, 0);
-
-    // Convert the image into a blob URI and use it as #test's src.
-    canvas.toBlob(function(blob) {
-      var uri = window.URL.createObjectURL(blob);
-      var testImage = document.getElementById('test');
-      
-      testImage.onload = testImage.onerror = function() {
-        // Take the snapshot.
-        document.documentElement.removeAttribute('class');
-      };
-
-      testImage.src = uri;
-    }, 'image/jpeg', 0.99);
-  }
-
-  // Start loading the image.
-  image.src = 'image.png';
-</script>
-
-</html>
diff --git a/image/test/reftest/blob/image.png b/image/test/reftest/blob/image.png
deleted file mode 100644
index d7d87adce0..0000000000
Binary files a/image/test/reftest/blob/image.png and /dev/null differ
diff --git a/image/test/reftest/blob/reftest.list b/image/test/reftest/blob/reftest.list
deleted file mode 100644
index e795ba9d38..0000000000
--- a/image/test/reftest/blob/reftest.list
+++ /dev/null
@@ -1,7 +0,0 @@
-# Blob URI tests 
-
-# Test that blob URIs don't get merged if they have different ref params.
-# (We run the test twice to check both cached and non-cached cases.)
-default-preferences pref(image.mozsamplesize.enabled,true)
-!= blob-uri-with-ref-param.html blob-uri-with-ref-param-notref.html
-!= blob-uri-with-ref-param.html blob-uri-with-ref-param-notref.html
diff --git a/image/test/reftest/jpeg/reftest.list b/image/test/reftest/jpeg/reftest.list
index 0eafb77e72..f48d3641aa 100644
--- a/image/test/reftest/jpeg/reftest.list
+++ b/image/test/reftest/jpeg/reftest.list
@@ -52,5 +52,3 @@ random-if(Android) == jpg-srgb-icc.jpg jpg-srgb-icc.png
 # "Here is the beginning of a boundary," and --$(boundary)-- means "All done
 # sending you parts.")
 HTTP == webcam-simulacrum.mjpg blue.jpg
-pref(image.mozsamplesize.enabled,true) fuzzy(21,256) == jpg-size-32x32.jpg#-moz-samplesize=2 jpg-size-16x16.png
-pref(image.mozsamplesize.enabled,true) fuzzy(92,16) == jpg-size-32x32.jpg#-moz-samplesize=8 jpg-size-4x4.png
diff --git a/image/test/reftest/reftest.list b/image/test/reftest/reftest.list
index 8547e50369..4658e42871 100644
--- a/image/test/reftest/reftest.list
+++ b/image/test/reftest/reftest.list
@@ -46,8 +46,5 @@ include color-management/reftest.list
 # Downscaling tests
 include downscaling/reftest.list
 
-# Blob URI tests
-include blob/reftest.list
-
 # Lossless encoders
 skip-if(Android) include encoders-lossless/reftest.list
diff --git a/ipc/glue/BackgroundParentImpl.cpp b/ipc/glue/BackgroundParentImpl.cpp
index 1d11ae8f6c..931bc5bc9c 100644
--- a/ipc/glue/BackgroundParentImpl.cpp
+++ b/ipc/glue/BackgroundParentImpl.cpp
@@ -40,7 +40,6 @@
 #include "mozilla/layout/VsyncParent.h"
 #include "mozilla/dom/network/UDPSocketParent.h"
 #include "mozilla/Preferences.h"
-#include "nsIAppsService.h"
 #include "nsNetUtil.h"
 #include "nsIScriptSecurityManager.h"
 #include "nsProxyRelease.h"
diff --git a/js/src/jsapi.cpp b/js/src/jsapi.cpp
index 5aa38917f5..74d54aae64 100644
--- a/js/src/jsapi.cpp
+++ b/js/src/jsapi.cpp
@@ -3826,7 +3826,6 @@ JS::TransitiveCompileOptions::copyPODTransitiveOptions(const TransitiveCompileOp
     asmJSOption = rhs.asmJSOption;
     throwOnAsmJSValidationFailureOption = rhs.throwOnAsmJSValidationFailureOption;
     forceAsync = rhs.forceAsync;
-    installedFile = rhs.installedFile;
     sourceIsLazy = rhs.sourceIsLazy;
     introductionType = rhs.introductionType;
     introductionLineno = rhs.introductionLineno;
diff --git a/js/src/jsapi.h b/js/src/jsapi.h
index 68e852e23f..1f4f52c3bb 100644
--- a/js/src/jsapi.h
+++ b/js/src/jsapi.h
@@ -3821,7 +3821,6 @@ class JS_FRIEND_API(TransitiveCompileOptions)
         asmJSOption(AsmJSOption::Disabled),
         throwOnAsmJSValidationFailureOption(false),
         forceAsync(false),
-        installedFile(false),
         sourceIsLazy(false),
         introductionType(nullptr),
         introductionLineno(0),
@@ -3856,7 +3855,6 @@ class JS_FRIEND_API(TransitiveCompileOptions)
     AsmJSOption asmJSOption;
     bool throwOnAsmJSValidationFailureOption;
     bool forceAsync;
-    bool installedFile;  // 'true' iff pre-compiling js file in packaged app
     bool sourceIsLazy;
 
     // |introductionType| is a statically allocated C string:
@@ -6300,17 +6298,14 @@ enum AsmJSCacheResult
  * outparams. If the callback returns 'true', the JS engine guarantees a call
  * to CloseAsmJSCacheEntryForWriteOp passing the same base address, size and
  * handle.
- *
- * If 'installed' is true, then the cache entry is associated with a permanently
- * installed JS file (e.g., in a packaged webapp). This information allows the
- * embedding to store the cache entry in a installed location associated with
- * the principal of 'global' where it will not be evicted until the associated
- * installed JS file is removed.
  */
 typedef AsmJSCacheResult
-(* OpenAsmJSCacheEntryForWriteOp)(HandleObject global, bool installed,
-                                  const char16_t* begin, const char16_t* end,
-                                  size_t size, uint8_t** memory, intptr_t* handle);
+(* OpenAsmJSCacheEntryForWriteOp)(HandleObject global,
+                                  const char16_t* begin,
+                                  const char16_t* end,
+                                  size_t size,
+                                  uint8_t** memory,
+                                  intptr_t* handle);
 typedef void
 (* CloseAsmJSCacheEntryForWriteOp)(size_t size, uint8_t* memory, intptr_t handle);
 
diff --git a/js/src/shell/js.cpp b/js/src/shell/js.cpp
index 1f89e38482..f844913e4d 100644
--- a/js/src/shell/js.cpp
+++ b/js/src/shell/js.cpp
@@ -7215,9 +7215,12 @@ ShellCloseAsmJSCacheEntryForRead(size_t serializedSize, const uint8_t* memory, i
 }
 
 static JS::AsmJSCacheResult
-ShellOpenAsmJSCacheEntryForWrite(HandleObject global, bool installed,
-                                 const char16_t* begin, const char16_t* end,
-                                 size_t serializedSize, uint8_t** memoryOut, intptr_t* handleOut)
+ShellOpenAsmJSCacheEntryForWrite(HandleObject global,
+                                 const char16_t* begin,
+                                 const char16_t* end,
+                                 size_t serializedSize,
+                                 uint8_t** memoryOut,
+                                 intptr_t* handleOut)
 {
     if (!jsCachingEnabled || !jsCacheAsmJSPath)
         return JS::AsmJSCache_Disabled_ShellFlags;
diff --git a/js/src/wasm/AsmJS.cpp b/js/src/wasm/AsmJS.cpp
index 03c40ab268..69788a852b 100644
--- a/js/src/wasm/AsmJS.cpp
+++ b/js/src/wasm/AsmJS.cpp
@@ -1,7 +1,7 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  *
  * Copyright 2014 Mozilla Foundation
- * Copyright 2022, 2023 Moonchild Productions
+ * Copyright 2022-2024 Moonchild Productions
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -6700,11 +6700,10 @@ StoreAsmJSModuleInCache(AsmJSParser& parser, Module& module, ExclusiveContext* c
 
     const char16_t* begin = parser.tokenStream.rawCharPtrAt(ModuleChars::beginOffset(parser));
     const char16_t* end = parser.tokenStream.rawCharPtrAt(ModuleChars::endOffset(parser));
-    bool installed = parser.options().installedFile;
 
     ScopedCacheEntryOpenedForWrite entry(cx, serializedSize);
     JS::AsmJSCacheResult openResult =
-        open(cx->global(), installed, begin, end, serializedSize, &entry.memory, &entry.handle);
+        open(cx->global(), begin, end, serializedSize, &entry.memory, &entry.handle);
     if (openResult != JS::AsmJSCache_Success)
         return openResult;
 
diff --git a/js/xpconnect/loader/mozJSSubScriptLoader.cpp b/js/xpconnect/loader/mozJSSubScriptLoader.cpp
index a278cffa5a..8844a1d929 100644
--- a/js/xpconnect/loader/mozJSSubScriptLoader.cpp
+++ b/js/xpconnect/loader/mozJSSubScriptLoader.cpp
@@ -848,7 +848,6 @@ ScriptPrecompiler::OnStreamComplete(nsIIncrementalStreamLoader* aLoader,
 
     JS::CompileOptions options(cx, JSVERSION_DEFAULT);
     options.forceAsync = true;
-    options.installedFile = true;
 
     nsCOMPtr<nsIURI> uri;
     mChannel->GetURI(getter_AddRefs(uri));
diff --git a/layout/base/nsIPresShell.h b/layout/base/nsIPresShell.h
index 5ae95d5825..248a7a4e67 100644
--- a/layout/base/nsIPresShell.h
+++ b/layout/base/nsIPresShell.h
@@ -201,18 +201,6 @@ public:
 
   bool IsDestroying() { return mIsDestroying; }
 
-  /**
-   * Make a one-way transition into a "zombie" state.  In this state,
-   * no reflow is done, no painting is done, and no refresh driver
-   * ticks are processed.  This is a dangerous state: it can leave
-   * areas of the composition target unpainted if callers aren't
-   * careful.  (Don't let your zombie presshell out of the shed.)
-   *
-   * This is used in cases where a presshell is created for reasons
-   * other than reflow/painting.
-   */
-  virtual void MakeZombie() = 0;
-
   /**
    * All frames owned by the shell are allocated from an arena.  They
    * are also recycled using free lists.  Separate free lists are
@@ -1784,7 +1772,6 @@ protected:
   bool                      mStylesHaveChanged : 1;
   bool                      mDidInitialize : 1;
   bool                      mIsDestroying : 1;
-  bool                      mIsZombie : 1;
   bool                      mIsReflowing : 1;
 
   // For all documents we initially lock down painting.
diff --git a/layout/base/nsPresShell.cpp b/layout/base/nsPresShell.cpp
index 666d4ff740..89c810bd41 100644
--- a/layout/base/nsPresShell.cpp
+++ b/layout/base/nsPresShell.cpp
@@ -1319,13 +1319,6 @@ PresShell::Destroy()
   mTouchManager.Destroy();
 }
 
-void
-PresShell::MakeZombie()
-{
-  mIsZombie = true;
-  CancelAllPendingReflows();
-}
-
 nsRefreshDriver*
 nsIPresShell::GetRefreshDriver() const
 {
@@ -3959,10 +3952,6 @@ PresShell::FlushPendingNotifications(mozFlushType aType)
 void
 PresShell::FlushPendingNotifications(mozilla::ChangesToFlush aFlush)
 {
-  if (mIsZombie) {
-    return;
-  }
-
   /**
    * VERY IMPORTANT: If you add some sort of new flushing to this
    * method, make sure to add the relevant SetNeedLayoutFlush or
@@ -6170,7 +6159,7 @@ PresShell::Paint(nsView*        aViewToPaint,
 
   MOZ_ASSERT(!mApproximateFrameVisibilityVisited, "Should have been cleared");
 
-  if (!mIsActive || mIsZombie) {
+  if (!mIsActive) {
     return;
   }
 
@@ -6886,20 +6875,6 @@ CheckPermissionForBeforeAfterKeyboardEvent(Element* aElement)
     if (permission == nsIPermissionManager::ALLOW_ACTION) {
       return true;
     }
-
-    // Check "embed-apps" permission for later use.
-    permission = nsIPermissionManager::DENY_ACTION;
-    permMgr->TestPermissionFromPrincipal(principal, "embed-apps", &permission);
-  }
-
-  // An element can handle before events and after events if the following
-  // conditions are met:
-  // 1) <iframe mozbrowser mozapp>
-  // 2) it has "embed-apps" permission.
-  nsCOMPtr<nsIMozBrowserFrame> browserFrame(do_QueryInterface(aElement));
-  if ((permission == nsIPermissionManager::ALLOW_ACTION) &&
-      browserFrame && browserFrame->GetReallyIsApp()) {
-    return true;
   }
 
   return false;
@@ -9042,10 +9017,6 @@ PresShell::ScheduleReflowOffTimer()
 bool
 PresShell::DoReflow(nsIFrame* target, bool aInterruptible)
 {
-  if (mIsZombie) {
-    return true;
-  }
-
   gfxTextPerfMetrics* tp = mPresContext->GetTextPerfMetrics();
   TimeStamp timeStart;
   if (tp) {
diff --git a/layout/base/nsPresShell.h b/layout/base/nsPresShell.h
index f47711253c..54ef6a3d96 100644
--- a/layout/base/nsPresShell.h
+++ b/layout/base/nsPresShell.h
@@ -102,7 +102,6 @@ public:
   void Init(nsIDocument* aDocument, nsPresContext* aPresContext,
             nsViewManager* aViewManager, nsStyleSet* aStyleSet);
   virtual void Destroy() override;
-  virtual void MakeZombie() override;
 
   virtual void UpdatePreferenceStyles() override;
 
diff --git a/layout/build/nsLayoutModule.cpp b/layout/build/nsLayoutModule.cpp
index 3c6f5f3aa5..bcde9a071c 100644
--- a/layout/build/nsLayoutModule.cpp
+++ b/layout/build/nsLayoutModule.cpp
@@ -79,7 +79,6 @@
 #include "DOMStorageManager.h"
 #include "nsJSON.h"
 #include "nsZipArchive.h"
-#include "mozIApplicationClearPrivateDataParams.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/dom/DOMException.h"
 #include "mozilla/dom/DOMRequest.h"
diff --git a/layout/build/nsLayoutStatics.cpp b/layout/build/nsLayoutStatics.cpp
index ab6af2eb21..ffdf624e49 100644
--- a/layout/build/nsLayoutStatics.cpp
+++ b/layout/build/nsLayoutStatics.cpp
@@ -282,8 +282,6 @@ nsLayoutStatics::Initialize()
 #ifdef MOZ_PERMISSIONS
   nsPermissionManager::ClearOriginDataObserverInit();
 #endif
-  nsCookieService::AppClearDataObserverInit();
-  nsApplicationCacheService::AppClearDataObserverInit();
 
   HTMLVideoElement::Init();
 
diff --git a/layout/generic/nsViewportFrame.cpp b/layout/generic/nsViewportFrame.cpp
index ab3bfc88c3..dac4f22f74 100644
--- a/layout/generic/nsViewportFrame.cpp
+++ b/layout/generic/nsViewportFrame.cpp
@@ -86,7 +86,7 @@ ShouldInTopLayerForFullscreen(Element* aElement)
     return false;
   }
   nsCOMPtr<nsIMozBrowserFrame> browserFrame = do_QueryInterface(aElement);
-  if (browserFrame && browserFrame->GetReallyIsBrowserOrApp()) {
+  if (browserFrame && browserFrame->GetReallyIsBrowser()) {
     return false;
   }
   return true;
diff --git a/layout/style/nsCSSRuleProcessor.cpp b/layout/style/nsCSSRuleProcessor.cpp
index 0a9c55fc17..6abfd57574 100644
--- a/layout/style/nsCSSRuleProcessor.cpp
+++ b/layout/style/nsCSSRuleProcessor.cpp
@@ -2310,7 +2310,7 @@ static bool SelectorMatches(Element* aElement,
           nsCOMPtr<nsIMozBrowserFrame>
             browserFrame = do_QueryInterface(aElement);
           if (!browserFrame ||
-              !browserFrame->GetReallyIsBrowserOrApp()) {
+              !browserFrame->GetReallyIsBrowser()) {
             return false;
           }
         }
diff --git a/layout/tools/reftest/reftest.jsm b/layout/tools/reftest/reftest.jsm
index cd2e02f27d..c013d3e1b2 100644
--- a/layout/tools/reftest/reftest.jsm
+++ b/layout/tools/reftest/reftest.jsm
@@ -1,4 +1,4 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 4 -*- /
+/* -*- indent-tabs-mode: nil; js-indent-level: 4 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
@@ -291,7 +291,6 @@ this.OnRefTestLoad = function OnRefTestLoad(win)
     if (gBrowserIsIframe) {
       gBrowser = gContainingWindow.document.createElementNS(XHTML_NS, "iframe");
       gBrowser.setAttribute("mozbrowser", "");
-      gBrowser.setAttribute("mozapp", prefs.getCharPref("b2g.system_manifest_url"));
     } else {
       gBrowser = gContainingWindow.document.createElementNS(XUL_NS, "xul:browser");
     }
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 883d5c2b48..13e6ec3570 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -959,8 +959,6 @@ pref("devtools.debugger.force-local", true);
 pref("devtools.debugger.prompt-connection", true);
 // Block tools from seeing / interacting with certified apps
 pref("devtools.debugger.forbid-certified-apps", true);
-// List of permissions that a sideloaded app can't ask for
-pref("devtools.apps.forbidden-permissions", "embed-apps");
 
 // DevTools default color unit
 pref("devtools.defaultColorUnit", "authored");
@@ -5049,9 +5047,6 @@ pref("layout.accessiblecaret.hide_carets_for_mouse_input", true);
 // Wakelock is disabled by default.
 pref("dom.wakelock.enabled", false);
 
-// disable mozsample size for now
-pref("image.mozsamplesize.enabled", false);
-
 pref("beacon.enabled", true);
 
 // Camera prefs
diff --git a/modules/libpref/test/unit_ipc/test_user_default_prefs.js b/modules/libpref/test/unit_ipc/test_user_default_prefs.js
index 3b8ca28c66..c39cae4d45 100644
--- a/modules/libpref/test/unit_ipc/test_user_default_prefs.js
+++ b/modules/libpref/test/unit_ipc/test_user_default_prefs.js
@@ -27,12 +27,6 @@ function run_test() {
     // We finish in clean_up()
     do_test_pending();
 
-    try {
-        if (pb.getCharPref('dom.ipc.processPrelaunch.enabled')) {
-            dump('WARNING: Content process may already have launched, so this test may not be meaningful.');
-        }
-    } catch(e) { }
-
     initialValue = pb.getCharPref(kPrefName);
 
     test_user_setting();
@@ -73,4 +67,4 @@ function clean_up() {
     check_child_pref_info_eq(function () {
             do_test_finished();
         });
-}
\ No newline at end of file
+}
diff --git a/netwerk/base/nsMediaFragmentURIParser.cpp b/netwerk/base/nsMediaFragmentURIParser.cpp
index b90d42fbb3..42dcd63bcf 100644
--- a/netwerk/base/nsMediaFragmentURIParser.cpp
+++ b/netwerk/base/nsMediaFragmentURIParser.cpp
@@ -334,19 +334,6 @@ bool nsMediaFragmentURIParser::ParseXYWH(nsDependentSubstring aString)
   return false;
 }
 
-bool nsMediaFragmentURIParser::ParseMozSampleSize(nsDependentSubstring aString)
-{
-  int32_t sampleSize;
-
-  // Read and validate coordinates.
-  if (ParseInteger(aString, sampleSize) && sampleSize > 0) {
-    mSampleSize.emplace(sampleSize);
-    return true;
-  }
-
-  return false;
-}
-
 void nsMediaFragmentURIParser::Parse(nsACString& aRef)
 {
   // Create an array of possibly-invalid media fragments.
@@ -367,9 +354,9 @@ void nsMediaFragmentURIParser::Parse(nsACString& aRef)
   }
 
   // Parse the media fragment values.
-  bool gotTemporal = false, gotSpatial = false, gotSampleSize = false;
+  bool gotTemporal = false, gotSpatial = false;
   for (int i = fragments.Length() - 1 ; i >= 0 ; --i) {
-    if (gotTemporal && gotSpatial && gotSampleSize) {
+    if (gotTemporal && gotSpatial) {
       // We've got one of each possible type. No need to look at the rest.
       break;
     } else if (!gotTemporal && fragments[i].first.EqualsLiteral("t")) {
@@ -378,9 +365,6 @@ void nsMediaFragmentURIParser::Parse(nsACString& aRef)
     } else if (!gotSpatial && fragments[i].first.EqualsLiteral("xywh")) {
       nsAutoString value = NS_ConvertUTF8toUTF16(fragments[i].second);
       gotSpatial = ParseXYWH(nsDependentSubstring(value, 0));
-    } else if (!gotSampleSize && fragments[i].first.EqualsLiteral("-moz-samplesize")) {
-      nsAutoString value = NS_ConvertUTF8toUTF16(fragments[i].second);
-      gotSampleSize = ParseMozSampleSize(nsDependentSubstring(value, 0));
     }
   }
 }
diff --git a/netwerk/base/nsMediaFragmentURIParser.h b/netwerk/base/nsMediaFragmentURIParser.h
index fdd9f60803..a5e678b635 100644
--- a/netwerk/base/nsMediaFragmentURIParser.h
+++ b/netwerk/base/nsMediaFragmentURIParser.h
@@ -63,10 +63,6 @@ public:
   // returns the unit used.
   ClipUnit GetClipUnit() const { return mClipUnit; }
 
-  bool HasSampleSize() const { return mSampleSize.isSome(); }
-
-  int GetSampleSize() const { return *mSampleSize; }
-
 private:
   // Parse the URI ref provided, looking for media fragments. This is
   // the top-level parser the invokes the others below.
@@ -88,14 +84,12 @@ private:
   bool ParseNPTMM(nsDependentSubstring& aString, uint32_t& aMinute);
   bool ParseNPTSS(nsDependentSubstring& aString, uint32_t& aSecond);
   bool ParseXYWH(nsDependentSubstring aString);
-  bool ParseMozSampleSize(nsDependentSubstring aString);
 
   // Media fragment information.
   Maybe<double>    mStart;
   Maybe<double>    mEnd;
   Maybe<nsIntRect> mClip;
   ClipUnit         mClipUnit;
-  Maybe<int>       mSampleSize;
 };
 
 } // namespace net
diff --git a/netwerk/base/nsNetUtil.cpp b/netwerk/base/nsNetUtil.cpp
index b9ec64ef84..ce62cfa8fc 100644
--- a/netwerk/base/nsNetUtil.cpp
+++ b/netwerk/base/nsNetUtil.cpp
@@ -12,7 +12,6 @@
 #include "mozilla/Preferences.h"
 #include "nsNetUtil.h"
 #include "nsNetUtilInlines.h"
-#include "mozIApplicationClearPrivateDataParams.h"
 #include "nsCategoryCache.h"
 #include "nsContentUtils.h"
 #include "nsHashKeys.h"
@@ -568,16 +567,7 @@ NS_LoadGroupMatchesPrincipal(nsILoadGroup *aLoadGroup,
                                   getter_AddRefs(loadContext));
     NS_ENSURE_TRUE(loadContext, false);
 
-    // Verify load context appId and browser flag match the principal
-    uint32_t contextAppId;
-    bool contextInIsolatedBrowser;
-    nsresult rv = loadContext->GetAppId(&contextAppId);
-    NS_ENSURE_SUCCESS(rv, false);
-    rv = loadContext->GetIsInIsolatedMozBrowserElement(&contextInIsolatedBrowser);
-    NS_ENSURE_SUCCESS(rv, false);
-
-    return contextAppId == aPrincipal->GetAppId() &&
-           contextInIsolatedBrowser == aPrincipal->GetIsInIsolatedMozBrowserElement();
+    return true;
 }
 
 nsresult
@@ -1333,39 +1323,6 @@ NS_HasBeenCrossOrigin(nsIChannel* aChannel, bool aReport)
   return NS_FAILED(loadingPrincipal->CheckMayLoad(uri, aReport, dataInherits));
 }
 
-nsresult
-NS_GetAppInfoFromClearDataNotification(nsISupports *aSubject,
-                                       uint32_t *aAppID,
-                                       bool *aBrowserOnly)
-{
-    nsresult rv;
-
-    nsCOMPtr<mozIApplicationClearPrivateDataParams>
-        clearParams(do_QueryInterface(aSubject));
-    MOZ_ASSERT(clearParams);
-    if (!clearParams) {
-        return NS_ERROR_UNEXPECTED;
-    }
-
-    uint32_t appId;
-    rv = clearParams->GetAppId(&appId);
-    MOZ_ASSERT(NS_SUCCEEDED(rv));
-    MOZ_ASSERT(appId != NECKO_UNKNOWN_APP_ID);
-    NS_ENSURE_SUCCESS(rv, rv);
-    if (appId == NECKO_UNKNOWN_APP_ID) {
-        return NS_ERROR_UNEXPECTED;
-    }
-
-    bool browserOnly = false;
-    rv = clearParams->GetBrowserOnly(&browserOnly);
-    MOZ_ASSERT(NS_SUCCEEDED(rv));
-    NS_ENSURE_SUCCESS(rv, rv);
-
-    *aAppID = appId;
-    *aBrowserOnly = browserOnly;
-    return NS_OK;
-}
-
 bool
 NS_ShouldCheckAppCache(nsIURI *aURI, bool usePrivateBrowsing)
 {
@@ -2385,39 +2342,18 @@ NS_CompareLoadInfoAndLoadContext(nsIChannel *aChannel)
     return NS_OK;
   }
 
-  uint32_t loadContextAppId = 0;
-  nsresult rv = loadContext->GetAppId(&loadContextAppId);
-  if (NS_FAILED(rv)) {
-    return NS_ERROR_UNEXPECTED;
-  }
-
-  bool loadContextIsInBE = false;
-  rv = loadContext->GetIsInIsolatedMozBrowserElement(&loadContextIsInBE);
-  if (NS_FAILED(rv)) {
-    return NS_ERROR_UNEXPECTED;
-  }
-
   OriginAttributes originAttrsLoadInfo = loadInfo->GetOriginAttributes();
   DocShellOriginAttributes originAttrsLoadContext;
   loadContext->GetOriginAttributes(originAttrsLoadContext);
 
-  LOG(("NS_CompareLoadInfoAndLoadContext - loadInfo: %d, %d, %d, %d; "
-       "loadContext: %d %d, %d, %d. [channel=%p]",
-       originAttrsLoadInfo.mAppId, originAttrsLoadInfo.mInIsolatedMozBrowser,
-       originAttrsLoadInfo.mUserContextId, originAttrsLoadInfo.mPrivateBrowsingId,
-       loadContextAppId, loadContextIsInBE,
-       originAttrsLoadContext.mUserContextId, originAttrsLoadContext.mPrivateBrowsingId,
+  LOG(("NS_CompareLoadInfoAndLoadContext - loadInfo: %d, %d; "
+       "loadContext: %d, %d. [channel=%p]",
+       originAttrsLoadInfo.mUserContextId,
+       originAttrsLoadInfo.mPrivateBrowsingId,
+       originAttrsLoadContext.mUserContextId,
+       originAttrsLoadContext.mPrivateBrowsingId,
        aChannel));
 
-  MOZ_ASSERT(originAttrsLoadInfo.mAppId == loadContextAppId,
-             "AppId in the loadContext and in the loadInfo are not the "
-             "same!");
-
-  MOZ_ASSERT(originAttrsLoadInfo.mInIsolatedMozBrowser ==
-             loadContextIsInBE,
-             "The value of InIsolatedMozBrowser in the loadContext and in "
-             "the loadInfo are not the same!");
-
   MOZ_ASSERT(originAttrsLoadInfo.mUserContextId ==
              originAttrsLoadContext.mUserContextId,
              "The value of mUserContextId in the loadContext and in the "
diff --git a/netwerk/base/nsNetUtil.h b/netwerk/base/nsNetUtil.h
index 53fa679879..f9645f4c60 100644
--- a/netwerk/base/nsNetUtil.h
+++ b/netwerk/base/nsNetUtil.h
@@ -682,15 +682,6 @@ bool NS_GetAppInfo(nsIChannel *aChannel,
                    uint32_t *aAppID,
                    bool *aIsInIsolatedMozBrowserElement);
 
-/**
- *  Gets appId and browserOnly parameters from the TOPIC_WEB_APP_CLEAR_DATA
- *  nsIObserverService notification.  Used when clearing user data or
- *  uninstalling web apps.
- */
-nsresult NS_GetAppInfoFromClearDataNotification(nsISupports *aSubject,
-                                                uint32_t *aAppID,
-                                                bool *aBrowserOnly);
-
 /**
  * Determines whether appcache should be checked for a given URI.
  */
diff --git a/netwerk/base/nsUDPSocket.cpp b/netwerk/base/nsUDPSocket.cpp
index 3cf45cf328..7aaf6b2654 100644
--- a/netwerk/base/nsUDPSocket.cpp
+++ b/netwerk/base/nsUDPSocket.cpp
@@ -612,8 +612,7 @@ nsUDPSocket::InitWithAddress(const NetAddr *aAddr, nsIPrincipal *aPrincipal,
 
   if (aPrincipal) {
     mAppId = aPrincipal->GetAppId();
-    mIsInIsolatedMozBrowserElement =
-      aPrincipal->GetIsInIsolatedMozBrowserElement();
+    mIsInIsolatedMozBrowserElement = false;
   }
 
   uint16_t port;
diff --git a/netwerk/cache/nsApplicationCacheService.cpp b/netwerk/cache/nsApplicationCacheService.cpp
index c512b91695..5420f2755f 100644
--- a/netwerk/cache/nsApplicationCacheService.cpp
+++ b/netwerk/cache/nsApplicationCacheService.cpp
@@ -7,7 +7,6 @@
 #include "nsCacheService.h"
 #include "nsApplicationCacheService.h"
 #include "nsCRT.h"
-#include "mozIApplicationClearPrivateDataParams.h"
 #include "nsNetCID.h"
 #include "nsNetUtil.h"
 #include "nsIObserverService.h"
@@ -253,14 +252,3 @@ private:
 NS_IMPL_ISUPPORTS(AppCacheClearDataObserver, nsIObserver)
 
 } // namespace
-
-// Instantiates and registers AppCacheClearDataObserver for notifications
-void
-nsApplicationCacheService::AppClearDataObserverInit()
-{
-  nsCOMPtr<nsIObserverService> observerService = services::GetObserverService();
-  if (observerService) {
-    RefPtr<AppCacheClearDataObserver> obs = new AppCacheClearDataObserver();
-    observerService->AddObserver(obs, "clear-origin-attributes-data", /*ownsWeak=*/ false);
-  }
-}
diff --git a/netwerk/cache/nsApplicationCacheService.h b/netwerk/cache/nsApplicationCacheService.h
index 73bd32206c..45623e50b9 100644
--- a/netwerk/cache/nsApplicationCacheService.h
+++ b/netwerk/cache/nsApplicationCacheService.h
@@ -18,8 +18,6 @@ public:
     NS_DECL_ISUPPORTS
     NS_DECL_NSIAPPLICATIONCACHESERVICE
 
-    static void AppClearDataObserverInit();
-
 private:
     ~nsApplicationCacheService();
     RefPtr<nsCacheService> mCacheService;
diff --git a/netwerk/cookie/nsCookieService.cpp b/netwerk/cookie/nsCookieService.cpp
index bdcb388373..9ffee5fa76 100644
--- a/netwerk/cookie/nsCookieService.cpp
+++ b/netwerk/cookie/nsCookieService.cpp
@@ -48,9 +48,6 @@
 #include "mozilla/storage.h"
 #include "mozilla/AutoRestore.h"
 #include "mozilla/FileUtils.h"
-#include "nsIAppsService.h"
-#include "mozIApplication.h"
-#include "mozIApplicationClearPrivateDataParams.h"
 #include "nsIConsoleService.h"
 #include "nsVariant.h"
 
@@ -675,15 +672,6 @@ nsCookieService::GetSingleton()
   return gCookieService;
 }
 
-/* static */ void
-nsCookieService::AppClearDataObserverInit()
-{
-  nsCOMPtr<nsIObserverService> observerService = services::GetObserverService();
-  nsCOMPtr<nsIObserver> obs = new AppClearDataObserver();
-  observerService->AddObserver(obs, TOPIC_CLEAR_ORIGIN_DATA,
-                               /* ownsWeak= */ false);
-}
-
 /******************************************************************************
  * nsCookieService impl:
  * public methods
diff --git a/netwerk/cookie/nsCookieService.h b/netwerk/cookie/nsCookieService.h
index deb9fed330..df83045243 100644
--- a/netwerk/cookie/nsCookieService.h
+++ b/netwerk/cookie/nsCookieService.h
@@ -260,14 +260,6 @@ class nsCookieService final : public nsICookieService
     static nsICookieService*      GetXPCOMSingleton();
     nsresult                      Init();
 
-  /**
-   * Start watching the observer service for messages indicating that an app has
-   * been uninstalled.  When an app is uninstalled, we get the cookie service
-   * (thus instantiating it, if necessary) and clear all the cookies for that
-   * app.
-   */
-  static void AppClearDataObserverInit();
-
   protected:
     virtual ~nsCookieService();
 
diff --git a/netwerk/dns/ChildDNSService.cpp b/netwerk/dns/ChildDNSService.cpp
index a3a1f3347b..c95c3551fe 100644
--- a/netwerk/dns/ChildDNSService.cpp
+++ b/netwerk/dns/ChildDNSService.cpp
@@ -202,6 +202,13 @@ ChildDNSService::GetDNSCacheEntries(nsTArray<mozilla::net::DNSCacheEntries> *arg
   return NS_ERROR_NOT_AVAILABLE;
 }
 
+NS_IMETHODIMP
+ChildDNSService::ClearCache()
+{
+  // Not available in IPC children.
+  return NS_ERROR_NOT_AVAILABLE;
+}
+
 NS_IMETHODIMP
 ChildDNSService::GetMyHostName(nsACString &result)
 {
diff --git a/netwerk/dns/nsDNSService2.cpp b/netwerk/dns/nsDNSService2.cpp
index e8e257d0f9..4ebfb647d8 100644
--- a/netwerk/dns/nsDNSService2.cpp
+++ b/netwerk/dns/nsDNSService2.cpp
@@ -1052,6 +1052,12 @@ nsDNSService::GetDNSCacheEntries(nsTArray<mozilla::net::DNSCacheEntries> *args)
     return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDNSService::ClearCache() {
+  mResolver->FlushCache();
+  return NS_OK;
+}
+
 size_t
 nsDNSService::SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const
 {
diff --git a/netwerk/dns/nsIDNSService.idl b/netwerk/dns/nsIDNSService.idl
index 2704790dc3..816d01dd60 100644
--- a/netwerk/dns/nsIDNSService.idl
+++ b/netwerk/dns/nsIDNSService.idl
@@ -115,6 +115,11 @@ interface nsIDNSService : nsISupports
      */
     [noscript] void getDNSCacheEntries(in EntriesArray args);
 
+    /**
+     * Clears the DNS cache.
+     */
+    void clearCache();
+
     /**
      * @return the hostname of the operating system.
      */
diff --git a/netwerk/ipc/NeckoParent.cpp b/netwerk/ipc/NeckoParent.cpp
index c3a288e689..3b00a15d29 100644
--- a/netwerk/ipc/NeckoParent.cpp
+++ b/netwerk/ipc/NeckoParent.cpp
@@ -34,7 +34,6 @@
 #include "mozilla/AppProcessChecker.h"
 #include "nsPrintfCString.h"
 #include "nsHTMLDNSPrefetch.h"
-#include "nsIAppsService.h"
 #include "nsEscape.h"
 #include "SerializedLoadContext.h"
 #include "nsAuthInformationHolder.h"
diff --git a/netwerk/protocol/http/HttpBaseChannel.cpp b/netwerk/protocol/http/HttpBaseChannel.cpp
index e0ccbfb811..3c5fa6763a 100644
--- a/netwerk/protocol/http/HttpBaseChannel.cpp
+++ b/netwerk/protocol/http/HttpBaseChannel.cpp
@@ -3010,12 +3010,8 @@ HttpBaseChannel::SetupReplacementChannel(nsIURI       *newURI,
 
       NeckoOriginAttributes attrs = newLoadInfo->GetOriginAttributes();
 
-      MOZ_ASSERT(docShellAttrs.mAppId == attrs.mAppId,
-                "docshell and necko should have the same appId attribute.");
       MOZ_ASSERT(docShellAttrs.mUserContextId == attrs.mUserContextId,
                 "docshell and necko should have the same userContextId attribute.");
-      MOZ_ASSERT(docShellAttrs.mInIsolatedMozBrowser == attrs.mInIsolatedMozBrowser,
-                "docshell and necko should have the same inIsolatedMozBrowser attribute.");
       MOZ_ASSERT(docShellAttrs.mPrivateBrowsingId == attrs.mPrivateBrowsingId,
                  "docshell and necko should have the same privateBrowsingId attribute.");
 
diff --git a/netwerk/protocol/http/nsHttpAuthCache.cpp b/netwerk/protocol/http/nsHttpAuthCache.cpp
index be5cd17a77..b5b6ee79f3 100644
--- a/netwerk/protocol/http/nsHttpAuthCache.cpp
+++ b/netwerk/protocol/http/nsHttpAuthCache.cpp
@@ -13,7 +13,6 @@
 #include "mozilla/Attributes.h"
 #include "nsString.h"
 #include "nsCRT.h"
-#include "mozIApplicationClearPrivateDataParams.h"
 #include "nsIObserverService.h"
 #include "mozilla/Services.h"
 #include "mozilla/DebugOnly.h"
diff --git a/netwerk/protocol/http/nsHttpHandler.cpp b/netwerk/protocol/http/nsHttpHandler.cpp
index d798fde2f7..8c6893d1fb 100644
--- a/netwerk/protocol/http/nsHttpHandler.cpp
+++ b/netwerk/protocol/http/nsHttpHandler.cpp
@@ -33,7 +33,6 @@
 #include "nsSocketTransportService2.h"
 #include "nsAlgorithm.h"
 #include "ASpdySession.h"
-#include "mozIApplicationClearPrivateDataParams.h"
 #include "EventTokenBucket.h"
 #include "Tickler.h"
 #include "nsIXULAppInfo.h"
@@ -404,7 +403,6 @@ nsHttpHandler::Init()
         obsService->AddObserver(this, "net:prune-all-connections", true);
         obsService->AddObserver(this, "net:failed-to-process-uri-content", true);
         obsService->AddObserver(this, "last-pb-context-exited", true);
-        obsService->AddObserver(this, "webapps-clear-data", true);
         obsService->AddObserver(this, "browser:purge-session-history", true);
         obsService->AddObserver(this, NS_NETWORK_LINK_TOPIC, true);
         obsService->AddObserver(this, "application-background", true);
@@ -2288,10 +2286,6 @@ nsHttpHandler::Observe(nsISupports *subject,
         if (mConnMgr) {
             mConnMgr->ClearAltServiceMappings();
         }
-    } else if (!strcmp(topic, "webapps-clear-data")) {
-        if (mConnMgr) {
-            mConnMgr->ClearAltServiceMappings();
-        }
     } else if (!strcmp(topic, "browser:purge-session-history")) {
         if (mConnMgr) {
             if (gSocketTransportService) {
diff --git a/netwerk/protocol/wyciwyg/nsWyciwygProtocolHandler.cpp b/netwerk/protocol/wyciwyg/nsWyciwygProtocolHandler.cpp
index 4e1f7c22e6..3bf1fedf76 100644
--- a/netwerk/protocol/wyciwyg/nsWyciwygProtocolHandler.cpp
+++ b/netwerk/protocol/wyciwyg/nsWyciwygProtocolHandler.cpp
@@ -11,7 +11,6 @@
 #include "nsServiceManagerUtils.h"
 #include "plstr.h"
 #include "nsIObserverService.h"
-#include "mozIApplicationClearPrivateDataParams.h"
 #include "nsIURI.h"
 
 #include "mozilla/net/NeckoChild.h"
diff --git a/netwerk/test/unit_ipc/child_app_offline_notifications.js b/netwerk/test/unit_ipc/child_app_offline_notifications.js
deleted file mode 100644
index 870c22b397..0000000000
--- a/netwerk/test/unit_ipc/child_app_offline_notifications.js
+++ /dev/null
@@ -1,43 +0,0 @@
-Cu.import("resource://gre/modules/Services.jsm");
-Cu.import("resource://gre/modules/XPCOMUtils.jsm");
-
-function is_app_offline(appId) {
-  let ioservice = Cc['@mozilla.org/network/io-service;1'].
-    getService(Ci.nsIIOService);
-  return ioservice.isAppOffline(appId);
-}
-
-var events_observed_no = 0;
-
-// Holds the last observed app-offline event
-var info = null;
-function observer(aSubject, aTopic, aData) {
-  events_observed_no++;
-  info = aSubject.QueryInterface(Ci.nsIAppOfflineInfo);
-  dump("ChildObserver - subject: {" + aSubject.appId + ", " + aSubject.mode + "} ");
-}
-
-// Add observer for the app-offline notification
-function run_test() {
-  Services.obs.addObserver(observer, "network:app-offline-status-changed", false);
-}
-
-// Chech that the app has the proper offline status
-function check_status(appId, status)
-{
-  do_check_eq(is_app_offline(appId), status == Ci.nsIAppOfflineInfo.OFFLINE);
-}
-
-// Check that the app has the proper offline status
-// and that the correct notification has been received
-function check_notification_and_status(appId, status) {
-  do_check_eq(info.appId, appId);
-  do_check_eq(info.mode, status);
-  do_check_eq(is_app_offline(appId), status == Ci.nsIAppOfflineInfo.OFFLINE);
-}
-
-// Remove the observer from the child process
-function finished() {
-  Services.obs.removeObserver(observer, "network:app-offline-status-changed");
-  do_check_eq(events_observed_no, 2);
-}
diff --git a/testing/mochitest/manifest.webapp b/testing/mochitest/manifest.webapp
index a3c2e2592b..a1c03e257b 100644
--- a/testing/mochitest/manifest.webapp
+++ b/testing/mochitest/manifest.webapp
@@ -24,7 +24,6 @@
     "desktop-notification":{},
     "idle":{},
     "network-events":{},
-    "embed-apps":{},
     "audio-channel-content":{},
     "audio-channel-alarm":{},
     "before-after-keyboard-event":{}
diff --git a/testing/specialpowers/content/SpecialPowersObserver.jsm b/testing/specialpowers/content/SpecialPowersObserver.jsm
index fc7584505e..0b44393fb9 100644
--- a/testing/specialpowers/content/SpecialPowersObserver.jsm
+++ b/testing/specialpowers/content/SpecialPowersObserver.jsm
@@ -87,7 +87,6 @@ SpecialPowersObserver.prototype._loadFrameScript = function()
     this._messageManager.addMessageListener("SPUnloadExtension", this);
     this._messageManager.addMessageListener("SPExtensionMessage", this);
     this._messageManager.addMessageListener("SPCleanUpSTSData", this);
-    this._messageManager.addMessageListener("SPClearAppPrivateData", this);
 
     this._messageManager.loadFrameScript(CHILD_LOGGER_SCRIPT, true);
     this._messageManager.loadFrameScript(CHILD_SCRIPT_API, true);
@@ -159,7 +158,6 @@ SpecialPowersObserver.prototype.uninit = function()
     this._messageManager.removeMessageListener("SPUnloadExtension", this);
     this._messageManager.removeMessageListener("SPExtensionMessage", this);
     this._messageManager.removeMessageListener("SPCleanUpSTSData", this);
-    this._messageManager.removeMessageListener("SPClearAppPrivateData", this);
 
     this._messageManager.removeDelayedFrameScript(CHILD_LOGGER_SCRIPT);
     this._messageManager.removeDelayedFrameScript(CHILD_SCRIPT_API);
diff --git a/testing/specialpowers/content/SpecialPowersObserverAPI.js b/testing/specialpowers/content/SpecialPowersObserverAPI.js
index f37f7bf0e9..d3137a42d4 100644
--- a/testing/specialpowers/content/SpecialPowersObserverAPI.js
+++ b/testing/specialpowers/content/SpecialPowersObserverAPI.js
@@ -601,28 +601,6 @@ SpecialPowersObserverAPI.prototype = {
         return undefined;
       }
 
-      case "SPClearAppPrivateData": {
-        let appId = aMessage.data.appId;
-        let browserOnly = aMessage.data.browserOnly;
-
-        let attributes = { appId: appId };
-        if (browserOnly) {
-          attributes.inIsolatedMozBrowser = true;
-        }
-        this._notifyCategoryAndObservers(null,
-                                         "clear-origin-attributes-data",
-                                         JSON.stringify(attributes));
-
-        let subject = {
-          appId: appId,
-          browserOnly: browserOnly,
-          QueryInterface: XPCOMUtils.generateQI([Ci.mozIApplicationClearPrivateDataParams])
-        };
-        this._notifyCategoryAndObservers(subject, "webapps-clear-data", null);
-
-        return undefined;
-      }
-
       default:
         throw new SpecialPowersError("Unrecognized Special Powers API");
     }
diff --git a/testing/specialpowers/content/specialpowers.js b/testing/specialpowers/content/specialpowers.js
index 09dbb52097..dae8584690 100644
--- a/testing/specialpowers/content/specialpowers.js
+++ b/testing/specialpowers/content/specialpowers.js
@@ -44,8 +44,7 @@ function SpecialPowers(window) {
                             "SPLoadExtension",
                             "SPStartupExtension",
                             "SPUnloadExtension",
-                            "SPExtensionMessage",
-                            "SPClearAppPrivateData"];
+                            "SPExtensionMessage"];
   addMessageListener("SPPingService", this._messageListener);
   addMessageListener("SpecialPowers.FilesCreated", this._messageListener);
   addMessageListener("SpecialPowers.FilesError", this._messageListener);
diff --git a/testing/specialpowers/content/specialpowersAPI.js b/testing/specialpowers/content/specialpowersAPI.js
index e97ad89c40..dc33cd8260 100644
--- a/testing/specialpowers/content/specialpowersAPI.js
+++ b/testing/specialpowers/content/specialpowersAPI.js
@@ -1766,16 +1766,6 @@ SpecialPowersAPI.prototype = {
       // It's an URL.
       let uri = Services.io.newURI(arg, null, null);
       principal = secMan.createCodebasePrincipal(uri, {});
-    } else if (arg.manifestURL) {
-      // It's a thing representing an app.
-      let appsSvc = Cc["@mozilla.org/AppsService;1"]
-                      .getService(Ci.nsIAppsService)
-      let app = appsSvc.getAppByManifestURL(arg.manifestURL);
-      if (!app) {
-        throw "No app for this manifest!";
-      }
-
-      principal = app.principal;
     } else if (arg.nodePrincipal) {
       // It's a document.
       // In some tests the arg is a wrapped DOM element, so we unwrap it first.
diff --git a/toolkit/content/aboutNetworking.js b/toolkit/content/aboutNetworking.js
index 9400ae9d70..633af63c0e 100644
--- a/toolkit/content/aboutNetworking.js
+++ b/toolkit/content/aboutNetworking.js
@@ -176,6 +176,14 @@ function init() {
     doLookup();
   });
 
+  let clearDNSCache = document.getElementById("clearDNSCache");
+  clearDNSCache.addEventListener("click", function() {
+    Cc["@mozilla.org/network/dns-service;1"]
+      .getService(Ci.nsIDNSService)
+      .clearCache();
+    requestAllNetworkingData();
+  });
+
   let setLogButton = document.getElementById("set-log-file-button");
   setLogButton.addEventListener("click", setLogFile);
 
diff --git a/toolkit/content/aboutNetworking.xhtml b/toolkit/content/aboutNetworking.xhtml
index 440ee78385..17bcc2ac49 100644
--- a/toolkit/content/aboutNetworking.xhtml
+++ b/toolkit/content/aboutNetworking.xhtml
@@ -96,6 +96,8 @@
           </div>
 
           <div id="dns" class="tab" hidden="true">
+              <button id="clearDNSCache">&aboutNetworking.clearDNSCache;</button>
+              <br/><br/>
               <table>
                   <thead>
                       <tr>
diff --git a/toolkit/locales/en-US/chrome/global/aboutNetworking.dtd b/toolkit/locales/en-US/chrome/global/aboutNetworking.dtd
index 4069e21c05..5674dfcd67 100644
--- a/toolkit/locales/en-US/chrome/global/aboutNetworking.dtd
+++ b/toolkit/locales/en-US/chrome/global/aboutNetworking.dtd
@@ -41,3 +41,4 @@
 <!ENTITY aboutNetworking.dnsLookupButton       "Resolve">
 <!ENTITY aboutNetworking.dnsDomain             "Domain">
 <!ENTITY aboutNetworking.dnsLookupTableColumn  "IPs">
+<!ENTITY aboutNetworking.clearDNSCache         "Clear DNS cache">
diff --git a/tools/lint/eslint/modules.json b/tools/lint/eslint/modules.json
index 1ff5469789..78efc21a2a 100644
--- a/tools/lint/eslint/modules.json
+++ b/tools/lint/eslint/modules.json
@@ -11,7 +11,6 @@
   "AlertsHelper.jsm": [],
   "AppData.jsm": ["makeFakeAppDir"],
   "AppInfo.jsm": ["newAppInfo", "getAppInfo", "updateAppInfo"],
-  "AppsServiceChild.jsm": ["DOMApplicationRegistry", "WrappedManifestCache"],
   "arrays.js": ["inArray", "getSet", "indexOf", "remove", "rindexOf", "compare"],
   "assertions.js": ["Assert", "Expect"],
   "async.js": ["Async"],
diff --git a/uriloader/prefetch/OfflineCacheUpdateParent.cpp b/uriloader/prefetch/OfflineCacheUpdateParent.cpp
index 0381ec3f62..76edf35aac 100644
--- a/uriloader/prefetch/OfflineCacheUpdateParent.cpp
+++ b/uriloader/prefetch/OfflineCacheUpdateParent.cpp
@@ -256,20 +256,6 @@ OfflineCacheUpdateParent::SetRemoteTabs(bool aUseRemoteTabs)
     return NS_ERROR_NOT_IMPLEMENTED;
 }
 
-NS_IMETHODIMP
-OfflineCacheUpdateParent::GetIsInIsolatedMozBrowserElement(bool *aIsInIsolatedMozBrowserElement)
-{
-    NS_ENSURE_TRUE(mLoadingPrincipal, NS_ERROR_UNEXPECTED);
-    return mLoadingPrincipal->GetIsInIsolatedMozBrowserElement(aIsInIsolatedMozBrowserElement);
-}
-
-NS_IMETHODIMP
-OfflineCacheUpdateParent::GetAppId(uint32_t *aAppId)
-{
-    NS_ENSURE_TRUE(mLoadingPrincipal, NS_ERROR_UNEXPECTED);
-    return mLoadingPrincipal->GetAppId(aAppId);
-}
-
 NS_IMETHODIMP
 OfflineCacheUpdateParent::GetOriginAttributes(JS::MutableHandleValue aAttrs)
 {
diff --git a/uriloader/prefetch/nsIOfflineCacheUpdate.idl b/uriloader/prefetch/nsIOfflineCacheUpdate.idl
index 1308a8de27..87ec120bc9 100644
--- a/uriloader/prefetch/nsIOfflineCacheUpdate.idl
+++ b/uriloader/prefetch/nsIOfflineCacheUpdate.idl
@@ -224,9 +224,9 @@ interface nsIOfflineCacheUpdateService : nsISupports {
 
     /**
      * Schedule a cache update for a given offline manifest using app cache
-     * bound to the given appID+inIsolatedMozBrowser flag.  If an existing update
-     * is scheduled or running, that update will be returned. Otherwise a new
-     * update will be scheduled.
+     * bound to the given appID flag.  If an existing update is scheduled or
+     * running, that update will be returned. Otherwise a new update will be
+     * scheduled.
      */
     nsIOfflineCacheUpdate scheduleAppUpdate(in nsIURI aManifestURI,
                                             in nsIURI aDocumentURI,
diff --git a/xpfe/appshell/nsContentTreeOwner.cpp b/xpfe/appshell/nsContentTreeOwner.cpp
index 8e9a065a9c..18b9d5211e 100644
--- a/xpfe/appshell/nsContentTreeOwner.cpp
+++ b/xpfe/appshell/nsContentTreeOwner.cpp
@@ -820,7 +820,7 @@ nsContentTreeOwner::ProvideWindow(mozIDOMWindowProxy* aParent,
   // open a modal-type window, we're going to create a new <iframe mozbrowser>
   // and return its window here.
   nsCOMPtr<nsIDocShell> docshell = do_GetInterface(aParent);
-  if (docshell && docshell->GetIsInMozBrowserOrApp() &&
+  if (docshell && docshell->GetIsInMozBrowser() &&
       !(aChromeFlags & (nsIWebBrowserChrome::CHROME_MODAL |
                         nsIWebBrowserChrome::CHROME_OPENAS_DIALOG |
                         nsIWebBrowserChrome::CHROME_OPENAS_CHROME))) {