diff --git a/configure.in b/configure.in
index 5cca6d4cd7..def965f976 100644
--- a/configure.in
+++ b/configure.in
@@ -2950,7 +2950,7 @@ dnl Checks for library functions.
 dnl ========================================================
 AC_PROG_GCC_TRADITIONAL
 AC_FUNC_MEMCMP
-AC_CHECK_FUNCS(stat64 lstat64 truncate64 statvfs64 statvfs statfs64 statfs getpagesize gmtime_r localtime_r arc4random arc4random_buf)
+AC_CHECK_FUNCS(stat64 lstat64 truncate64 statvfs64 statvfs statfs64 statfs getpagesize gmtime_r localtime_r arc4random arc4random_buf mallinfo)
 
 dnl check for clock_gettime(), the CLOCK_MONOTONIC clock
 AC_CACHE_CHECK(for clock_gettime(CLOCK_MONOTONIC),
diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp
index 471c41ef6c..603d44009e 100644
--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -2905,7 +2905,7 @@ Element::CheckHandleEventForLinksPrecondition(EventChainVisitor& aVisitor,
       (!aVisitor.mEvent->mFlags.mIsTrusted &&
        (aVisitor.mEvent->mMessage != eMouseClick) &&
        (aVisitor.mEvent->mMessage != eKeyPress) &&
-       (aVisitor.mEvent->mMessage != NS_UI_ACTIVATE)) ||
+       (aVisitor.mEvent->mMessage != eLegacyDOMActivate)) ||
       !aVisitor.mPresContext ||
       aVisitor.mEvent->mFlags.mMultipleActionsPrevented) {
     return false;
@@ -2922,9 +2922,9 @@ Element::PreHandleEventForLinks(EventChainPreVisitor& aVisitor)
   // IMPORTANT: this switch and the switch below it must be kept in sync!
   switch (aVisitor.mEvent->mMessage) {
   case eMouseOver:
-  case NS_FOCUS_CONTENT:
+  case eFocus:
   case eMouseOut:
-  case NS_BLUR_CONTENT:
+  case eBlur:
     break;
   default:
     return NS_OK;
@@ -2945,7 +2945,7 @@ Element::PreHandleEventForLinks(EventChainPreVisitor& aVisitor)
   case eMouseOver:
     aVisitor.mEventStatus = nsEventStatus_eConsumeNoDefault;
     // FALL THROUGH
-  case NS_FOCUS_CONTENT: {
+  case eFocus: {
     InternalFocusEvent* focusEvent = aVisitor.mEvent->AsFocusEvent();
     if (!focusEvent || !focusEvent->isRefocus) {
       nsAutoString target;
@@ -2960,7 +2960,7 @@ Element::PreHandleEventForLinks(EventChainPreVisitor& aVisitor)
   case eMouseOut:
     aVisitor.mEventStatus = nsEventStatus_eConsumeNoDefault;
     // FALL THROUGH
-  case NS_BLUR_CONTENT:
+  case eBlur:
     rv = LeaveLink(aVisitor.mPresContext);
     if (NS_SUCCEEDED(rv)) {
       aVisitor.mEvent->mFlags.mMultipleActionsPrevented = true;
@@ -2984,7 +2984,7 @@ Element::PostHandleEventForLinks(EventChainPostVisitor& aVisitor)
   switch (aVisitor.mEvent->mMessage) {
   case eMouseDown:
   case eMouseClick:
-  case NS_UI_ACTIVATE:
+  case eLegacyDOMActivate:
   case eKeyPress:
     break;
   default:
@@ -3038,7 +3038,7 @@ Element::PostHandleEventForLinks(EventChainPostVisitor& aVisitor)
         nsEventStatus status = nsEventStatus_eIgnore;
         // DOMActive event should be trusted since the activation is actually
         // occurred even if the cause is an untrusted click event.
-        InternalUIEvent actEvent(true, NS_UI_ACTIVATE, mouseEvent);
+        InternalUIEvent actEvent(true, eLegacyDOMActivate, mouseEvent);
         actEvent.detail = 1;
 
         rv = shell->HandleDOMEventWithTarget(this, &actEvent, &status);
@@ -3049,7 +3049,7 @@ Element::PostHandleEventForLinks(EventChainPostVisitor& aVisitor)
     }
     break;
   }
-  case NS_UI_ACTIVATE:
+  case eLegacyDOMActivate:
     {
       if (aVisitor.mEvent->originalTarget == this) {
         nsAutoString target;
diff --git a/dom/base/FragmentOrElement.cpp b/dom/base/FragmentOrElement.cpp
index 3179e1bf52..719f3e14ef 100644
--- a/dom/base/FragmentOrElement.cpp
+++ b/dom/base/FragmentOrElement.cpp
@@ -679,8 +679,8 @@ nsIContent::PreHandleEvent(EventChainPreVisitor& aVisitor)
   bool isAnonForEvents = IsRootOfChromeAccessOnlySubtree();
   if ((aVisitor.mEvent->mMessage == eMouseOver ||
        aVisitor.mEvent->mMessage == eMouseOut ||
-       aVisitor.mEvent->mMessage == NS_POINTER_OVER ||
-       aVisitor.mEvent->mMessage == NS_POINTER_OUT) &&
+       aVisitor.mEvent->mMessage == ePointerOver ||
+       aVisitor.mEvent->mMessage == ePointerOut) &&
       // Check if we should stop event propagation when event has just been
       // dispatched or when we're about to propagate from
       // chrome access only subtree or if we are about to propagate out of
@@ -806,12 +806,12 @@ nsIContent::PreHandleEvent(EventChainPreVisitor& aVisitor)
     //   selectstart
     bool stopEvent = false;
     switch (aVisitor.mEvent->mMessage) {
-      case NS_IMAGE_ABORT:
-      case NS_LOAD_ERROR:
-      case NS_FORM_SELECTED:
-      case NS_FORM_CHANGE:
-      case NS_LOAD:
-      case NS_FORM_RESET:
+      case eImageAbort:
+      case eLoadError:
+      case eFormSelect:
+      case eFormChange:
+      case eLoad:
+      case eFormReset:
       case eResize:
       case eScroll:
       case NS_SELECT_START:
@@ -843,7 +843,7 @@ nsIContent::PreHandleEvent(EventChainPreVisitor& aVisitor)
       // The load event is special in that we don't ever propagate it
       // to chrome.
       nsCOMPtr<nsPIDOMWindow> win = OwnerDoc()->GetWindow();
-      EventTarget* parentTarget = win && aVisitor.mEvent->mMessage != NS_LOAD
+      EventTarget* parentTarget = win && aVisitor.mEvent->mMessage != eLoad
         ? win->GetParentTarget() : nullptr;
 
       aVisitor.mParentTarget = parentTarget;
diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
index ce0891c72e..3fb408e1ff 100644
--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -5448,7 +5448,7 @@ nsContentUtils::SetDataTransferInEvent(WidgetDragEvent* aDragEvent)
   // created before the event fires, so it should already be set. For other
   // drag events, get the object from the drag session.
   NS_ASSERTION(aDragEvent->mMessage != NS_DRAGDROP_GESTURE &&
-               aDragEvent->mMessage != NS_DRAGDROP_START,
+               aDragEvent->mMessage != eDragStart,
                "draggesture event created without a dataTransfer");
 
   nsCOMPtr<nsIDragSession> dragSession = GetDragSession();
@@ -5475,7 +5475,7 @@ nsContentUtils::SetDataTransferInEvent(WidgetDragEvent* aDragEvent)
   }
 
   bool isCrossDomainSubFrameDrop = false;
-  if (aDragEvent->mMessage == NS_DRAGDROP_DROP ||
+  if (aDragEvent->mMessage == eDrop ||
       aDragEvent->mMessage == NS_DRAGDROP_DRAGDROP) {
     isCrossDomainSubFrameDrop = CheckForSubFrameDrop(dragSession, aDragEvent);
   }
@@ -5497,7 +5497,7 @@ nsContentUtils::SetDataTransferInEvent(WidgetDragEvent* aDragEvent)
     aDragEvent->dataTransfer->GetEffectAllowedInt(&effectAllowed);
     aDragEvent->dataTransfer->SetDropEffectInt(FilterDropEffect(action, effectAllowed));
   }
-  else if (aDragEvent->mMessage == NS_DRAGDROP_DROP ||
+  else if (aDragEvent->mMessage == eDrop ||
            aDragEvent->mMessage == NS_DRAGDROP_DRAGDROP ||
            aDragEvent->mMessage == NS_DRAGDROP_END) {
     // For the drop and dragend events, set the drop effect based on the
@@ -7849,7 +7849,7 @@ nsContentUtils::SendMouseEvent(nsCOMPtr<nsIPresShell> aPresShell,
   else if (aType.EqualsLiteral("mouseout"))
     msg = eMouseExitFromWidget;
   else if (aType.EqualsLiteral("contextmenu")) {
-    msg = NS_CONTEXTMENU;
+    msg = eContextMenu;
     contextMenuKey = (aButton == 0);
   } else if (aType.EqualsLiteral("MozMouseHittest"))
     msg = eMouseHitTest;
diff --git a/dom/base/nsDOMWindowUtils.cpp b/dom/base/nsDOMWindowUtils.cpp
index c12f07f6da..2ec2ef3275 100644
--- a/dom/base/nsDOMWindowUtils.cpp
+++ b/dom/base/nsDOMWindowUtils.cpp
@@ -700,15 +700,15 @@ nsDOMWindowUtils::SendPointerEventCommon(const nsAString& aType,
 
   EventMessage msg;
   if (aType.EqualsLiteral("pointerdown")) {
-    msg = NS_POINTER_DOWN;
+    msg = ePointerDown;
   } else if (aType.EqualsLiteral("pointerup")) {
-    msg = NS_POINTER_UP;
+    msg = ePointerUp;
   } else if (aType.EqualsLiteral("pointermove")) {
-    msg = NS_POINTER_MOVE;
+    msg = ePointerMove;
   } else if (aType.EqualsLiteral("pointerover")) {
-    msg = NS_POINTER_OVER;
+    msg = ePointerOver;
   } else if (aType.EqualsLiteral("pointerout")) {
-    msg = NS_POINTER_OUT;
+    msg = ePointerOut;
   } else {
     return NS_ERROR_FAILURE;
   }
diff --git a/dom/base/nsDocument.cpp b/dom/base/nsDocument.cpp
index ed343cdc18..c43f4db4ad 100644
--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -8106,7 +8106,7 @@ nsDocument::PreHandleEvent(EventChainPreVisitor& aVisitor)
   aVisitor.mForceContentDispatch = true;
 
   // Load events must not propagate to |window| object, see bug 335251.
-  if (aVisitor.mEvent->mMessage != NS_LOAD) {
+  if (aVisitor.mEvent->mMessage != eLoad) {
     nsGlobalWindow* window = static_cast<nsGlobalWindow*>(GetWindow());
     aVisitor.mParentTarget =
       window ? window->GetTargetForEventTargetChain() : nullptr;
diff --git a/dom/base/nsFocusManager.cpp b/dom/base/nsFocusManager.cpp
index fc4c6f81f4..ea569f1261 100644
--- a/dom/base/nsFocusManager.cpp
+++ b/dom/base/nsFocusManager.cpp
@@ -963,7 +963,7 @@ nsFocusManager::WindowHidden(nsIDOMWindow* aWindow)
     window->UpdateCommands(NS_LITERAL_STRING("focus"), nullptr, 0);
 
     if (presShell) {
-      SendFocusOrBlurEvent(NS_BLUR_CONTENT, presShell,
+      SendFocusOrBlurEvent(eBlur, presShell,
                            oldFocusedContent->GetComposedDoc(),
                            oldFocusedContent, 1, false);
     }
@@ -1678,7 +1678,7 @@ nsFocusManager::Blur(nsPIDOMWindow* aWindowToClear,
     if (mActiveWindow)
       window->UpdateCommands(NS_LITERAL_STRING("focus"), nullptr, 0);
 
-    SendFocusOrBlurEvent(NS_BLUR_CONTENT, presShell,
+    SendFocusOrBlurEvent(eBlur, presShell,
                          content->GetComposedDoc(), content, 1, false);
   }
 
@@ -1725,9 +1725,9 @@ nsFocusManager::Blur(nsPIDOMWindow* aWindowToClear,
     // the document isn't null in case someone closed it during the blur above
     nsIDocument* doc = window->GetExtantDoc();
     if (doc)
-      SendFocusOrBlurEvent(NS_BLUR_CONTENT, presShell, doc, doc, 1, false);
+      SendFocusOrBlurEvent(eBlur, presShell, doc, doc, 1, false);
     if (mFocusedWindow == nullptr)
-      SendFocusOrBlurEvent(NS_BLUR_CONTENT, presShell, doc, window, 1, false);
+      SendFocusOrBlurEvent(eBlur, presShell, doc, window, 1, false);
 
     // check if a different window was focused
     result = (mFocusedWindow == nullptr && mActiveWindow);
@@ -1853,10 +1853,10 @@ nsFocusManager::Focus(nsPIDOMWindow* aWindow,
                                      GetFocusMoveActionCause(aFlags));
     }
     if (doc)
-      SendFocusOrBlurEvent(NS_FOCUS_CONTENT, presShell, doc,
+      SendFocusOrBlurEvent(eFocus, presShell, doc,
                            doc, aFlags & FOCUSMETHOD_MASK, aWindowRaised);
     if (mFocusedWindow == aWindow && mFocusedContent == nullptr)
-      SendFocusOrBlurEvent(NS_FOCUS_CONTENT, presShell, doc,
+      SendFocusOrBlurEvent(eFocus, presShell, doc,
                            aWindow, aFlags & FOCUSMETHOD_MASK, aWindowRaised);
   }
 
@@ -1904,7 +1904,7 @@ nsFocusManager::Focus(nsPIDOMWindow* aWindow,
       if (!aWindowRaised)
         aWindow->UpdateCommands(NS_LITERAL_STRING("focus"), nullptr, 0);
 
-      SendFocusOrBlurEvent(NS_FOCUS_CONTENT, presShell,
+      SendFocusOrBlurEvent(eFocus, presShell,
                            aContent->GetComposedDoc(),
                            aContent, aFlags & FOCUSMETHOD_MASK,
                            aWindowRaised, isRefocus);
@@ -1997,8 +1997,7 @@ nsFocusManager::SendFocusOrBlurEvent(EventMessage aEventMessage,
                                      bool aWindowRaised,
                                      bool aIsRefocus)
 {
-  NS_ASSERTION(aEventMessage == NS_FOCUS_CONTENT ||
-               aEventMessage == NS_BLUR_CONTENT,
+  NS_ASSERTION(aEventMessage == eFocus || aEventMessage == eBlur,
                "Wrong event type for SendFocusOrBlurEvent");
 
   nsCOMPtr<EventTarget> eventTarget = do_QueryInterface(aTarget);
@@ -2038,7 +2037,7 @@ nsFocusManager::SendFocusOrBlurEvent(EventMessage aEventMessage,
 #ifdef ACCESSIBILITY
   nsAccessibilityService* accService = GetAccService();
   if (accService) {
-    if (aEventMessage == NS_FOCUS_CONTENT) {
+    if (aEventMessage == eFocus) {
       accService->NotifyOfDOMFocus(aTarget);
     } else {
       accService->NotifyOfDOMBlur(aTarget);
diff --git a/dom/base/nsFocusManager.h b/dom/base/nsFocusManager.h
index 73fa2e9cf0..a2aad11dce 100644
--- a/dom/base/nsFocusManager.h
+++ b/dom/base/nsFocusManager.h
@@ -280,7 +280,7 @@ protected:
   /**
    * Fires a focus or blur event at aTarget.
    *
-   * aEventMessage should be either NS_FOCUS_CONTENT or NS_BLUR_CONTENT.
+   * aEventMessage should be either eFocus or eBlur.
    * For blur events, aFocusMethod should normally be non-zero.
    *
    * aWindowRaised should only be true if called from WindowRaised.
diff --git a/dom/base/nsGenConImageContent.cpp b/dom/base/nsGenConImageContent.cpp
index 5a8f5e26fb..0dbfa08ea3 100644
--- a/dom/base/nsGenConImageContent.cpp
+++ b/dom/base/nsGenConImageContent.cpp
@@ -49,8 +49,8 @@ public:
   virtual nsresult PreHandleEvent(EventChainPreVisitor& aVisitor) override
   {
     MOZ_ASSERT(IsInNativeAnonymousSubtree());
-    if (aVisitor.mEvent->mMessage == NS_LOAD ||
-        aVisitor.mEvent->mMessage == NS_LOAD_ERROR) {
+    if (aVisitor.mEvent->mMessage == eLoad ||
+        aVisitor.mEvent->mMessage == eLoadError) {
       // Don't propagate the events to the parent.
       return NS_OK;
     }
diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index 90f6fee629..57b0e64ec4 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -3260,8 +3260,8 @@ nsGlobalWindow::PostHandleEvent(EventChainPostVisitor& aVisitor)
   // Return early if there is nothing to do.
   switch (aVisitor.mEvent->mMessage) {
     case eResize:
-    case NS_PAGE_UNLOAD:
-    case NS_LOAD:
+    case eUnload:
+    case eLoad:
       break;
     default:
       return NS_OK;
@@ -3275,7 +3275,7 @@ nsGlobalWindow::PostHandleEvent(EventChainPostVisitor& aVisitor)
 
   if (aVisitor.mEvent->mMessage == eResize) {
     mIsHandlingResizeEvent = false;
-  } else if (aVisitor.mEvent->mMessage == NS_PAGE_UNLOAD &&
+  } else if (aVisitor.mEvent->mMessage == eUnload &&
              aVisitor.mEvent->mFlags.mIsTrusted) {
     // Execute bindingdetached handlers before we tear ourselves
     // down.
@@ -3283,7 +3283,7 @@ nsGlobalWindow::PostHandleEvent(EventChainPostVisitor& aVisitor)
       mDoc->BindingManager()->ExecuteDetachedHandlers();
     }
     mIsDocumentLoaded = false;
-  } else if (aVisitor.mEvent->mMessage == NS_LOAD &&
+  } else if (aVisitor.mEvent->mMessage == eLoad &&
              aVisitor.mEvent->mFlags.mIsTrusted) {
     // This is page load event since load events don't propagate to |window|.
     // @see nsDocument::PreHandleEvent.
@@ -3297,7 +3297,7 @@ nsGlobalWindow::PostHandleEvent(EventChainPostVisitor& aVisitor)
       // onload event for the frame element.
 
       nsEventStatus status = nsEventStatus_eIgnore;
-      WidgetEvent event(aVisitor.mEvent->mFlags.mIsTrusted, NS_LOAD);
+      WidgetEvent event(aVisitor.mEvent->mFlags.mIsTrusted, eLoad);
       event.mFlags.mBubbles = false;
 
       // Most of the time we could get a pres context to pass in here,
diff --git a/dom/base/nsScriptElement.cpp b/dom/base/nsScriptElement.cpp
index ef7ec836f0..a63557151e 100644
--- a/dom/base/nsScriptElement.cpp
+++ b/dom/base/nsScriptElement.cpp
@@ -59,10 +59,10 @@ nsScriptElement::ScriptEvaluated(nsresult aResult,
       nsContentUtils::GetContextForContent(cont);
 
     nsEventStatus status = nsEventStatus_eIgnore;
-    EventMessage message = NS_SUCCEEDED(aResult) ? NS_LOAD : NS_LOAD_ERROR;
+    EventMessage message = NS_SUCCEEDED(aResult) ? eLoad : eLoadError;
     WidgetEvent event(true, message);
     // Load event doesn't bubble.
-    event.mFlags.mBubbles = (message != NS_LOAD);
+    event.mFlags.mBubbles = (message != eLoad);
 
     EventDispatcher::Dispatch(cont, presContext, &event, nullptr, &status);
   }
diff --git a/dom/events/DataTransfer.cpp b/dom/events/DataTransfer.cpp
index bbea2f2b73..464edfda74 100644
--- a/dom/events/DataTransfer.cpp
+++ b/dom/events/DataTransfer.cpp
@@ -68,40 +68,41 @@ const char DataTransfer::sEffects[8][9] = {
   "none", "copy", "move", "copyMove", "link", "copyLink", "linkMove", "all"
 };
 
-DataTransfer::DataTransfer(nsISupports* aParent, uint32_t aEventType,
+DataTransfer::DataTransfer(nsISupports* aParent, EventMessage aEventMessage,
                            bool aIsExternal, int32_t aClipboardType)
-  : mParent(aParent),
-    mEventType(aEventType),
-    mDropEffect(nsIDragService::DRAGDROP_ACTION_NONE),
-    mEffectAllowed(nsIDragService::DRAGDROP_ACTION_UNINITIALIZED),
-    mCursorState(false),
-    mReadOnly(true),
-    mIsExternal(aIsExternal),
-    mUserCancelled(false),
-    mIsCrossDomainSubFrameDrop(false),
-    mClipboardType(aClipboardType),
-    mDragImageX(0),
-    mDragImageY(0)
+  : mParent(aParent)
+  , mDropEffect(nsIDragService::DRAGDROP_ACTION_NONE)
+  , mEffectAllowed(nsIDragService::DRAGDROP_ACTION_UNINITIALIZED)
+  , mEventMessage(aEventMessage)
+  , mCursorState(false)
+  , mReadOnly(true)
+  , mIsExternal(aIsExternal)
+  , mUserCancelled(false)
+  , mIsCrossDomainSubFrameDrop(false)
+  , mClipboardType(aClipboardType)
+  , mDragImageX(0)
+  , mDragImageY(0)
 {
   // For these events, we want to be able to add data to the data transfer, so
   // clear the readonly state. Otherwise, the data is already present. For
   // external usage, cache the data from the native clipboard or drag.
-  if (aEventType == NS_CUT ||
-      aEventType == NS_COPY ||
-      aEventType == NS_DRAGDROP_START ||
-      aEventType == NS_DRAGDROP_GESTURE) {
+  if (aEventMessage == NS_CUT ||
+      aEventMessage == NS_COPY ||
+      aEventMessage == eDragStart ||
+      aEventMessage == NS_DRAGDROP_GESTURE) {
     mReadOnly = false;
   } else if (mIsExternal) {
-    if (aEventType == NS_PASTE) {
+    if (aEventMessage == NS_PASTE) {
       CacheExternalClipboardFormats();
-    } else if (aEventType >= NS_DRAGDROP_EVENT_START && aEventType <= NS_DRAGDROP_LEAVE) {
+    } else if (aEventMessage >= eDragDropEventFirst &&
+               aEventMessage <= eDragDropEventLast) {
       CacheExternalDragFormats();
     }
   }
 }
 
 DataTransfer::DataTransfer(nsISupports* aParent,
-                           uint32_t aEventType,
+                           EventMessage aEventMessage,
                            const uint32_t aEffectAllowed,
                            bool aCursorState,
                            bool aIsExternal,
@@ -112,20 +113,20 @@ DataTransfer::DataTransfer(nsISupports* aParent,
                            Element* aDragImage,
                            uint32_t aDragImageX,
                            uint32_t aDragImageY)
-  : mParent(aParent),
-    mEventType(aEventType),
-    mDropEffect(nsIDragService::DRAGDROP_ACTION_NONE),
-    mEffectAllowed(aEffectAllowed),
-    mCursorState(aCursorState),
-    mReadOnly(true),
-    mIsExternal(aIsExternal),
-    mUserCancelled(aUserCancelled),
-    mIsCrossDomainSubFrameDrop(aIsCrossDomainSubFrameDrop),
-    mClipboardType(aClipboardType),
-    mItems(aItems),
-    mDragImage(aDragImage),
-    mDragImageX(aDragImageX),
-    mDragImageY(aDragImageY)
+  : mParent(aParent)
+  , mDropEffect(nsIDragService::DRAGDROP_ACTION_NONE)
+  , mEffectAllowed(aEffectAllowed)
+  , mEventMessage(aEventMessage)
+  , mCursorState(aCursorState)
+  , mReadOnly(true)
+  , mIsExternal(aIsExternal)
+  , mUserCancelled(aUserCancelled)
+  , mIsCrossDomainSubFrameDrop(aIsCrossDomainSubFrameDrop)
+  , mClipboardType(aClipboardType)
+  , mItems(aItems)
+  , mDragImage(aDragImage)
+  , mDragImageX(aDragImageX)
+  , mDragImageY(aDragImageY)
 {
   MOZ_ASSERT(mParent);
   // The items are copied from aItems into mItems. There is no need to copy
@@ -133,8 +134,8 @@ DataTransfer::DataTransfer(nsISupports* aParent,
   // draggesture and dragstart events are the only times when items are
   // modifiable, but those events should have been using the first constructor
   // above.
-  NS_ASSERTION(aEventType != NS_DRAGDROP_GESTURE &&
-               aEventType != NS_DRAGDROP_START,
+  NS_ASSERTION(aEventMessage != NS_DRAGDROP_GESTURE &&
+               aEventMessage != eDragStart,
                "invalid event type for DataTransfer constructor");
 }
 
@@ -268,8 +269,9 @@ DataTransfer::GetMozUserCancelled(bool* aUserCancelled)
 FileList*
 DataTransfer::GetFiles(ErrorResult& aRv)
 {
-  if (mEventType != NS_DRAGDROP_DROP && mEventType != NS_DRAGDROP_DRAGDROP &&
-      mEventType != NS_PASTE) {
+  if (mEventMessage != eDrop &&
+      mEventMessage != NS_DRAGDROP_DRAGDROP &&
+      mEventMessage != NS_PASTE) {
     return nullptr;
   }
 
@@ -524,7 +526,8 @@ DataTransfer::MozTypesAt(uint32_t aIndex, ErrorResult& aRv) const
 {
   // Only the first item is valid for clipboard events
   if (aIndex > 0 &&
-      (mEventType == NS_CUT || mEventType == NS_COPY || mEventType == NS_PASTE)) {
+      (mEventMessage == NS_CUT || mEventMessage == NS_COPY ||
+       mEventMessage == NS_PASTE)) {
     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return nullptr;
   }
@@ -582,7 +585,8 @@ DataTransfer::MozGetDataAt(const nsAString& aFormat, uint32_t aIndex,
 
   // Only the first item is valid for clipboard events
   if (aIndex > 0 &&
-      (mEventType == NS_CUT || mEventType == NS_COPY || mEventType == NS_PASTE)) {
+      (mEventMessage == NS_CUT || mEventMessage == NS_COPY ||
+       mEventMessage == NS_PASTE)) {
     return NS_ERROR_DOM_INDEX_SIZE_ERR;
   }
 
@@ -611,8 +615,9 @@ DataTransfer::MozGetDataAt(const nsAString& aFormat, uint32_t aIndex,
   // only allow access to the data with the same principal.
   nsIPrincipal* principal = nullptr;
   if (mIsCrossDomainSubFrameDrop ||
-      (mEventType != NS_DRAGDROP_DROP && mEventType != NS_DRAGDROP_DRAGDROP &&
-       mEventType != NS_PASTE &&
+      (mEventMessage != eDrop &&
+       mEventMessage != NS_DRAGDROP_DRAGDROP &&
+       mEventMessage != NS_PASTE &&
        !nsContentUtils::IsCallerChrome())) {
     principal = nsContentUtils::SubjectPrincipal();
   }
@@ -703,7 +708,8 @@ DataTransfer::MozSetDataAt(const nsAString& aFormat, nsIVariant* aData,
 
   // Only the first item is valid for clipboard events
   if (aIndex > 0 &&
-      (mEventType == NS_CUT || mEventType == NS_COPY || mEventType == NS_PASTE)) {
+      (mEventMessage == NS_CUT || mEventMessage == NS_COPY ||
+       mEventMessage == NS_PASTE)) {
     return NS_ERROR_DOM_INDEX_SIZE_ERR;
   }
 
@@ -756,7 +762,8 @@ DataTransfer::MozClearDataAt(const nsAString& aFormat, uint32_t aIndex,
 
   // Only the first item is valid for clipboard events
   if (aIndex > 0 &&
-      (mEventType == NS_CUT || mEventType == NS_COPY || mEventType == NS_PASTE)) {
+      (mEventMessage == NS_CUT || mEventMessage == NS_COPY ||
+       mEventMessage == NS_PASTE)) {
     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return;
   }
@@ -771,8 +778,8 @@ DataTransfer::MozClearDataAtHelper(const nsAString& aFormat, uint32_t aIndex,
   MOZ_ASSERT(!mReadOnly);
   MOZ_ASSERT(aIndex < mItems.Length());
   MOZ_ASSERT(aIndex == 0 ||
-             (mEventType != NS_CUT && mEventType != NS_COPY &&
-              mEventType != NS_PASTE));
+             (mEventMessage != NS_CUT && mEventMessage != NS_COPY &&
+              mEventMessage != NS_PASTE));
 
   nsAutoString format;
   GetRealFormat(aFormat, format);
@@ -954,12 +961,12 @@ DataTransfer::AddElement(nsIDOMElement* aElement)
 }
 
 nsresult
-DataTransfer::Clone(nsISupports* aParent, uint32_t aEventType,
+DataTransfer::Clone(nsISupports* aParent, EventMessage aEventMessage,
                     bool aUserCancelled, bool aIsCrossDomainSubFrameDrop,
                     DataTransfer** aNewDataTransfer)
 {
   DataTransfer* newDataTransfer =
-    new DataTransfer(aParent, aEventType, mEffectAllowed, mCursorState,
+    new DataTransfer(aParent, aEventMessage, mEffectAllowed, mCursorState,
                      mIsExternal, aUserCancelled, aIsCrossDomainSubFrameDrop,
                      mClipboardType, mItems, mDragImage, mDragImageX,
                      mDragImageY);
@@ -1268,7 +1275,8 @@ DataTransfer::CacheExternalDragFormats()
 void
 DataTransfer::CacheExternalClipboardFormats()
 {
-  NS_ASSERTION(mEventType == NS_PASTE, "caching clipboard data for invalid event");
+  NS_ASSERTION(mEventMessage == NS_PASTE,
+               "caching clipboard data for invalid event");
 
   // Called during the constructor for paste events to cache the formats
   // available on the clipboard. As with CacheExternalDragFormats, the
@@ -1309,7 +1317,7 @@ DataTransfer::FillInExternalData(TransferItem& aItem, uint32_t aIndex)
   }
 
   // only drag and paste events should be calling FillInExternalData
-  NS_ASSERTION(mEventType != NS_CUT && mEventType != NS_COPY,
+  NS_ASSERTION(mEventMessage != NS_CUT && mEventMessage != NS_COPY,
                "clipboard event with empty data");
 
     NS_ConvertUTF16toUTF8 utf8format(aItem.mFormat);
@@ -1327,7 +1335,7 @@ DataTransfer::FillInExternalData(TransferItem& aItem, uint32_t aIndex)
   trans->Init(nullptr);
   trans->AddDataFlavor(format);
 
-  if (mEventType == NS_PASTE) {
+  if (mEventMessage == NS_PASTE) {
     MOZ_ASSERT(aIndex == 0, "index in clipboard must be 0");
 
     nsCOMPtr<nsIClipboard> clipboard = do_GetService("@mozilla.org/widget/clipboard;1");
diff --git a/dom/events/DataTransfer.h b/dom/events/DataTransfer.h
index 3926c031eb..f2a3afcc4d 100644
--- a/dom/events/DataTransfer.h
+++ b/dom/events/DataTransfer.h
@@ -18,6 +18,7 @@
 
 #include "nsAutoPtr.h"
 #include "mozilla/Attributes.h"
+#include "mozilla/EventForwards.h"
 #include "mozilla/dom/File.h"
 #include "mozilla/dom/Promise.h"
 
@@ -75,7 +76,7 @@ protected:
   // this constructor is used only by the Clone method to copy the fields as
   // needed to a new data transfer.
   DataTransfer(nsISupports* aParent,
-               uint32_t aEventType,
+               EventMessage aEventMessage,
                const uint32_t aEffectAllowed,
                bool aCursorState,
                bool aIsExternal,
@@ -95,8 +96,6 @@ public:
 
   // Constructor for DataTransfer.
   //
-  // aEventType is an event constant (such as NS_DRAGDROP_START)
-  //
   // aIsExternal must only be true when used to create a dataTransfer for a
   // paste or a drag that was started without using a data transfer. The
   // latter will occur when an external drag occurs, that is, a drag where the
@@ -104,8 +103,8 @@ public:
   // service directly. For clipboard operations, aClipboardType indicates
   // which clipboard to use, from nsIClipboard, or -1 for non-clipboard operations,
   // or if access to the system clipboard should not be allowed.
-  DataTransfer(nsISupports* aParent, uint32_t aEventType, bool aIsExternal,
-               int32_t aClipboardType);
+  DataTransfer(nsISupports* aParent, EventMessage aEventMessage,
+               bool aIsExternal, int32_t aClipboardType);
 
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
   nsISupports* GetParentObject()
@@ -222,8 +221,9 @@ public:
     return mDragImage;
   }
 
-  nsresult Clone(nsISupports* aParent, uint32_t aEventType, bool aUserCancelled,
-                 bool aIsCrossDomainSubFrameDrop, DataTransfer** aResult);
+  nsresult Clone(nsISupports* aParent, EventMessage aEventMessage,
+                 bool aUserCancelled, bool aIsCrossDomainSubFrameDrop,
+                 DataTransfer** aResult);
 
 protected:
 
@@ -254,14 +254,15 @@ protected:
 
   nsCOMPtr<nsISupports> mParent;
 
-  // the event type this data transfer is for. This will correspond to an
-  // event->mMessage value.
-  uint32_t mEventType;
 
   // the drop effect and effect allowed
   uint32_t mDropEffect;
   uint32_t mEffectAllowed;
 
+  // the event message this data transfer is for. This will correspond to an
+  // event->mMessage value.
+  EventMessage mEventMessage;
+
   // Indicates the behavior of the cursor during drag operations
   bool mCursorState;
 
diff --git a/dom/events/Event.cpp b/dom/events/Event.cpp
index ae7713b204..30a716bec7 100644
--- a/dom/events/Event.cpp
+++ b/dom/events/Event.cpp
@@ -716,12 +716,12 @@ Event::GetEventPopupControlState(WidgetEvent* aEvent, nsIDOMEvent* aDOMEvent)
     // nsPresShell::HandleEventInternal() for details.
     if (EventStateManager::IsHandlingUserInput()) {
       switch(aEvent->mMessage) {
-      case NS_FORM_SELECTED :
+      case eFormSelect:
         if (PopupAllowedForEvent("select")) {
           abuse = openControlled;
         }
         break;
-      case NS_FORM_CHANGE :
+      case eFormChange:
         if (PopupAllowedForEvent("change")) {
           abuse = openControlled;
         }
@@ -753,7 +753,7 @@ Event::GetEventPopupControlState(WidgetEvent* aEvent, nsIDOMEvent* aDOMEvent)
     // nsPresShell::HandleEventInternal() for details.
     if (EventStateManager::IsHandlingUserInput()) {
       switch(aEvent->mMessage) {
-      case NS_FORM_CHANGE :
+      case eFormChange:
         if (PopupAllowedForEvent("change")) {
           abuse = openControlled;
         }
@@ -853,12 +853,12 @@ Event::GetEventPopupControlState(WidgetEvent* aEvent, nsIDOMEvent* aDOMEvent)
     // nsPresShell::HandleEventInternal() for details.
     if (EventStateManager::IsHandlingUserInput()) {
       switch(aEvent->mMessage) {
-      case NS_FORM_SUBMIT :
+      case eFormSubmit:
         if (PopupAllowedForEvent("submit")) {
           abuse = openControlled;
         }
         break;
-      case NS_FORM_RESET :
+      case eFormReset:
         if (PopupAllowedForEvent("reset")) {
           abuse = openControlled;
         }
diff --git a/dom/events/EventListenerManager.cpp b/dom/events/EventListenerManager.cpp
index f963eda39d..3368b28883 100644
--- a/dom/events/EventListenerManager.cpp
+++ b/dom/events/EventListenerManager.cpp
@@ -1369,8 +1369,8 @@ EventListenerManager::HasUnloadListeners()
   uint32_t count = mListeners.Length();
   for (uint32_t i = 0; i < count; ++i) {
     Listener* listener = &mListeners.ElementAt(i);
-    if (listener->mEventMessage == NS_PAGE_UNLOAD ||
-        listener->mEventMessage == NS_BEFORE_PAGE_UNLOAD) {
+    if (listener->mEventMessage == eUnload ||
+        listener->mEventMessage == eBeforeUnload) {
       return true;
     }
   }
diff --git a/dom/events/EventNameList.h b/dom/events/EventNameList.h
index 88048c081a..09cc1b15d9 100644
--- a/dom/events/EventNameList.h
+++ b/dom/events/EventNameList.h
@@ -149,7 +149,7 @@
 #endif /* BEFOREUNLOAD_EVENT */
 
 EVENT(abort,
-      NS_IMAGE_ABORT,
+      eImageAbort,
       EventNameType_All,
       eBasicEventClass)
 EVENT(canplay,
@@ -161,7 +161,7 @@ EVENT(canplaythrough,
       EventNameType_HTML,
       eBasicEventClass)
 EVENT(change,
-      NS_FORM_CHANGE,
+      eFormChange,
       EventNameType_HTMLXUL,
       eBasicEventClass)
 EVENT(click,
@@ -169,7 +169,7 @@ EVENT(click,
       EventNameType_All,
       eMouseEventClass)
 EVENT(contextmenu,
-      NS_CONTEXTMENU,
+      eContextMenu,
       EventNameType_HTMLXUL,
       eMouseEventClass)
 // Not supported yet
@@ -191,7 +191,7 @@ EVENT(dragenter,
       EventNameType_HTMLXUL,
       eDragEventClass)
 EVENT(dragleave,
-      NS_DRAGDROP_LEAVE,
+      eDragLeave,
       EventNameType_HTMLXUL,
       eDragEventClass)
 EVENT(dragover,
@@ -199,11 +199,11 @@ EVENT(dragover,
       EventNameType_HTMLXUL,
       eDragEventClass)
 EVENT(dragstart,
-      NS_DRAGDROP_START,
+      eDragStart,
       EventNameType_HTMLXUL,
       eDragEventClass)
 EVENT(drop,
-      NS_DRAGDROP_DROP,
+      eDrop,
       EventNameType_HTMLXUL,
       eDragEventClass)
 EVENT(durationchange,
@@ -223,7 +223,7 @@ EVENT(input,
       EventNameType_HTMLXUL,
       eEditorInputEventClass)
 EVENT(invalid,
-      NS_FORM_INVALID,
+      eFormInvalid,
       EventNameType_HTMLXUL,
       eBasicEventClass)
 EVENT(keydown,
@@ -311,15 +311,15 @@ EVENT(mozpointerlockerror,
       EventNameType_HTML,
       eBasicEventClass)
 EVENT(pointerdown,
-      NS_POINTER_DOWN,
+      ePointerDown,
       EventNameType_All,
       ePointerEventClass)
 EVENT(pointermove,
-      NS_POINTER_MOVE,
+      ePointerMove,
       EventNameType_All,
       ePointerEventClass)
 EVENT(pointerup,
-      NS_POINTER_UP,
+      ePointerUp,
       EventNameType_All,
       ePointerEventClass)
 EVENT(pointercancel,
@@ -327,15 +327,15 @@ EVENT(pointercancel,
       EventNameType_All,
       ePointerEventClass)
 EVENT(pointerover,
-      NS_POINTER_OVER,
+      ePointerOver,
       EventNameType_All,
       ePointerEventClass)
 EVENT(pointerout,
-      NS_POINTER_OUT,
+      ePointerOut,
       EventNameType_All,
       ePointerEventClass)
 EVENT(pointerenter,
-      NS_POINTER_ENTER,
+      ePointerEnter,
       EventNameType_All,
       ePointerEventClass)
 EVENT(pointerleave,
@@ -378,7 +378,7 @@ EVENT(ratechange,
       EventNameType_HTML,
       eBasicEventClass)
 EVENT(reset,
-      NS_FORM_RESET,
+      eFormReset,
       EventNameType_HTMLXUL,
       eBasicEventClass)
 EVENT(seeked,
@@ -390,7 +390,7 @@ EVENT(seeking,
       EventNameType_HTML,
       eBasicEventClass)
 EVENT(select,
-      NS_FORM_SELECTED,
+      eFormSelect,
       EventNameType_HTMLXUL,
       eBasicEventClass)
 EVENT(show,
@@ -402,7 +402,7 @@ EVENT(stalled,
       EventNameType_HTML,
       eBasicEventClass)
 EVENT(submit,
-      NS_FORM_SUBMIT,
+      eFormSubmit,
       EventNameType_HTMLXUL,
       eBasicEventClass)
 EVENT(suspend,
@@ -452,19 +452,19 @@ EVENT(afterscriptexecute,
       eBasicEventClass)
 
 FORWARDED_EVENT(blur,
-                NS_BLUR_CONTENT,
+                eBlur,
                 EventNameType_HTMLXUL,
                 eFocusEventClass)
 ERROR_EVENT(error,
-            NS_LOAD_ERROR,
+            eLoadError,
             EventNameType_All,
             eBasicEventClass)
 FORWARDED_EVENT(focus,
-                NS_FOCUS_CONTENT,
+                eFocus,
                 EventNameType_HTMLXUL,
                 eFocusEventClass)
 FORWARDED_EVENT(load,
-                NS_LOAD,
+                eLoad,
                 EventNameType_All,
                 eBasicEventClass)
 FORWARDED_EVENT(resize,
@@ -485,11 +485,11 @@ WINDOW_EVENT(beforeprint,
              EventNameType_XUL | EventNameType_HTMLBodyOrFramesetOnly,
              eBasicEventClass)
 BEFOREUNLOAD_EVENT(beforeunload,
-                   NS_BEFORE_PAGE_UNLOAD,
+                   eBeforeUnload,
                    EventNameType_XUL | EventNameType_HTMLBodyOrFramesetOnly,
                    eBasicEventClass)
 WINDOW_EVENT(hashchange,
-             NS_HASHCHANGE,
+             eHashChange,
              EventNameType_XUL | EventNameType_HTMLBodyOrFramesetOnly,
              eBasicEventClass)
 WINDOW_EVENT(languagechange,
@@ -520,7 +520,7 @@ WINDOW_EVENT(pageshow,
              EventNameType_HTMLBodyOrFramesetOnly,
              eBasicEventClass)
 WINDOW_EVENT(popstate,
-             NS_POPSTATE,
+             ePopState,
              EventNameType_XUL | EventNameType_HTMLBodyOrFramesetOnly,
              eBasicEventClass)
 // Not supported yet
@@ -530,7 +530,7 @@ WINDOW_EVENT(popstate,
 // Not supported yet
 // WINDOW_EVENT(undo)
 WINDOW_EVENT(unload,
-             NS_PAGE_UNLOAD,
+             eUnload,
              (EventNameType_XUL | EventNameType_SVGSVG |
               EventNameType_HTMLBodyOrFramesetOnly),
              eBasicEventClass)
@@ -589,7 +589,7 @@ TOUCH_EVENT(touchcancel,
             eTouchEventClass)
 
 DOCUMENT_ONLY_EVENT(readystatechange,
-                    NS_READYSTATECHANGE,
+                    eReadyStateChange,
                     EventNameType_HTMLXUL,
                     eBasicEventClass)
 DOCUMENT_ONLY_EVENT(selectionchange,
@@ -636,15 +636,15 @@ NON_IDL_EVENT(DOMSubtreeModified,
               eMutationEventClass)
 
 NON_IDL_EVENT(DOMActivate,
-              NS_UI_ACTIVATE,
+              eLegacyDOMActivate,
               EventNameType_HTMLXUL,
               eUIEventClass)
 NON_IDL_EVENT(DOMFocusIn,
-              NS_UI_FOCUSIN,
+              eLegacyDOMFocusIn,
               EventNameType_HTMLXUL,
               eUIEventClass)
 NON_IDL_EVENT(DOMFocusOut,
-              NS_UI_FOCUSOUT,
+              eLegacyDOMFocusOut,
               EventNameType_HTMLXUL,
               eUIEventClass)
                                   
diff --git a/dom/events/EventStateManager.cpp b/dom/events/EventStateManager.cpp
index 9ad032f48f..0dcb12256a 100644
--- a/dom/events/EventStateManager.cpp
+++ b/dom/events/EventStateManager.cpp
@@ -520,7 +520,7 @@ EventStateManager::PreHandleEvent(nsPresContext* aPresContext,
     if (node &&
         (aEvent->mMessage == eKeyUp || aEvent->mMessage == eMouseUp ||
          aEvent->mMessage == NS_WHEEL_WHEEL || aEvent->mMessage == NS_TOUCH_END ||
-         aEvent->mMessage == NS_POINTER_UP)) {
+         aEvent->mMessage == ePointerUp)) {
       nsIDocument* doc = node->OwnerDoc();
       while (doc && !doc->UserHasInteracted()) {
         doc->SetUserHasInteracted(true);
@@ -559,7 +559,7 @@ EventStateManager::PreHandleEvent(nsPresContext* aPresContext,
   *aStatus = nsEventStatus_eIgnore;
 
   switch (aEvent->mMessage) {
-  case NS_CONTEXTMENU:
+  case eContextMenu:
     if (sIsPointerLocked) {
       return NS_ERROR_DOM_INVALID_STATE_ERR;
     }
@@ -646,8 +646,8 @@ EventStateManager::PreHandleEvent(nsPresContext* aPresContext,
       break;
     }
   case eMouseMove:
-  case NS_POINTER_DOWN:
-  case NS_POINTER_MOVE: {
+  case ePointerDown:
+  case ePointerMove: {
     // on the Mac, GenerateDragGesture() may not return until the drag
     // has completed and so |aTargetFrame| may have been deleted (moving
     // a bookmark, for example).  If this is the case, however, we know
@@ -670,8 +670,8 @@ EventStateManager::PreHandleEvent(nsPresContext* aPresContext,
     }
     break;
   case NS_DRAGDROP_OVER:
-    // NS_DRAGDROP_DROP is fired before NS_DRAGDROP_DRAGDROP so send
-    // the enter/exit events before NS_DRAGDROP_DROP.
+    // eDrop is fired before NS_DRAGDROP_DRAGDROP so send
+    // the enter/exit events before eDrop.
     GenerateDragDropEnterExit(aPresContext, aEvent->AsDragEvent());
     break;
 
@@ -1190,7 +1190,7 @@ CrossProcessSafeEvent(const WidgetEvent& aEvent)
     case eMouseDown:
     case eMouseUp:
     case eMouseMove:
-    case NS_CONTEXTMENU:
+    case eContextMenu:
     case eMouseEnterIntoWidget:
     case eMouseExitFromWidget:
       return true;
@@ -1211,7 +1211,7 @@ CrossProcessSafeEvent(const WidgetEvent& aEvent)
     switch (aEvent.mMessage) {
     case NS_DRAGDROP_OVER:
     case NS_DRAGDROP_EXIT:
-    case NS_DRAGDROP_DROP:
+    case eDrop:
       return true;
     default:
       break;
@@ -1468,7 +1468,7 @@ EventStateManager::FireContextClick()
 
     if (allowedToDispatch) {
       // init the event while mCurrentTarget is still good
-      WidgetMouseEvent event(true, NS_CONTEXTMENU, targetWidget,
+      WidgetMouseEvent event(true, eContextMenu, targetWidget,
                              WidgetMouseEvent::eReal);
       event.clickCount = 1;
       FillInEventFromGestureDown(&event);
@@ -1494,7 +1494,7 @@ EventStateManager::FireContextClick()
                                 nullptr, &status);
 
       // We don't need to dispatch to frame handling because no frames
-      // watch NS_CONTEXTMENU except for nsMenuFrame and that's only for
+      // watch eContextMenu except for nsMenuFrame and that's only for
       // dismissal. That's just as well since we don't really know
       // which frame to send it to.
     }
@@ -1653,7 +1653,7 @@ EventStateManager::GenerateDragGesture(nsPresContext* aPresContext,
         return;
 
       nsRefPtr<DataTransfer> dataTransfer =
-        new DataTransfer(window, NS_DRAGDROP_START, false, -1);
+        new DataTransfer(window, eDragStart, false, -1);
 
       nsCOMPtr<nsISelection> selection;
       nsCOMPtr<nsIContent> eventContent, targetContent;
@@ -1679,7 +1679,7 @@ EventStateManager::GenerateDragGesture(nsPresContext* aPresContext,
 
       // get the widget from the target frame
       WidgetDragEvent startEvent(aEvent->mFlags.mIsTrusted,
-                                 NS_DRAGDROP_START, widget);
+                                 eDragStart, widget);
       FillInEventFromGestureDown(&startEvent);
 
       WidgetDragEvent gestureEvent(aEvent->mFlags.mIsTrusted,
@@ -3024,7 +3024,7 @@ EventStateManager::PostHandleEvent(nsPresContext* aPresContext,
     // This break was commented specially
     // break;
   }
-  case NS_POINTER_UP: {
+  case ePointerUp: {
     WidgetPointerEvent* pointerEvent = aEvent->AsPointerEvent();
     // After UP/Cancel Touch pointers become invalid so we can remove relevant helper from Table
     // Mouse/Pen pointers are valid all the time (not only between down/up)
@@ -3302,7 +3302,7 @@ EventStateManager::PostHandleEvent(nsPresContext* aPresContext,
     }
     break;
 
-  case NS_DRAGDROP_DROP:
+  case eDrop:
     {
       // now fire the dragdrop event, for compatibility with XUL
       if (mCurrentTarget && nsEventStatus_eConsumeNoDefault != *aStatus) {
@@ -3891,8 +3891,7 @@ public:
 
   ~EnterLeaveDispatcher()
   {
-    if (mEventMessage == eMouseEnter ||
-        mEventMessage == NS_POINTER_ENTER) {
+    if (mEventMessage == eMouseEnter || mEventMessage == ePointerEnter) {
       for (int32_t i = mTargets.Count() - 1; i >= 0; --i) {
         mESM->DispatchMouseOrPointerEvent(mMouseEvent, mEventMessage,
                                           mTargets[i], mRelatedTarget);
@@ -3973,7 +3972,7 @@ EventStateManager::NotifyMouseOut(WidgetMouseEvent* aMouseEvent,
                                        isPointer ? ePointerLeave : eMouseLeave);
 
   // Fire mouseout
-  DispatchMouseOrPointerEvent(aMouseEvent, isPointer ? ePointerLeave : eMouseOut,
+  DispatchMouseOrPointerEvent(aMouseEvent, isPointer ? ePointerOut : eMouseOut,
                               wrapper->mLastOverElement, aMovingInto);
 
   wrapper->mLastOverFrame = nullptr;
@@ -4030,7 +4029,7 @@ EventStateManager::NotifyMouseOver(WidgetMouseEvent* aMouseEvent,
   Maybe<EnterLeaveDispatcher> enterDispatcher;
   if (dispatch) {
     enterDispatcher.emplace(this, aContent, lastOverElement, aMouseEvent,
-                            isPointer ? NS_POINTER_ENTER : eMouseEnter);
+                            isPointer ? ePointerEnter : eMouseEnter);
   }
 
   NotifyMouseOut(aMouseEvent, aContent);
@@ -4047,7 +4046,7 @@ EventStateManager::NotifyMouseOver(WidgetMouseEvent* aMouseEvent,
     // Fire mouseover
     wrapper->mLastOverFrame = 
       DispatchMouseOrPointerEvent(aMouseEvent,
-                                  isPointer ? NS_POINTER_OVER : eMouseOver,
+                                  isPointer ? ePointerOver : eMouseOver,
                                   aContent, lastOverElement);
     wrapper->mLastOverElement = aContent;
   } else {
@@ -4169,8 +4168,8 @@ EventStateManager::GenerateMouseEnterExit(WidgetMouseEvent* aMouseEvent)
       sLastRefPoint = aMouseEvent->refPoint;
 
     }
-  case NS_POINTER_MOVE:
-  case NS_POINTER_DOWN:
+  case ePointerMove:
+  case ePointerDown:
     {
       // Get the target content target (mousemove target == mouseover target)
       nsCOMPtr<nsIContent> targetElement = GetEventTargetContent(aMouseEvent);
@@ -4185,7 +4184,7 @@ EventStateManager::GenerateMouseEnterExit(WidgetMouseEvent* aMouseEvent)
       }
     }
     break;
-  case NS_POINTER_UP:
+  case ePointerUp:
     {
       // Get the target content target (mousemove target == mouseover target)
       nsCOMPtr<nsIContent> targetElement = GetEventTargetContent(aMouseEvent);
@@ -4346,7 +4345,7 @@ EventStateManager::GenerateDragDropEnterExit(nsPresContext* aPresContext,
 
         if (sLastDragOverFrame) {
           FireDragEnterOrExit(sLastDragOverFrame->PresContext(),
-                              aDragEvent, NS_DRAGDROP_LEAVE,
+                              aDragEvent, eDragLeave,
                               targetContent, lastContent, sLastDragOverFrame);
         }
 
@@ -4368,7 +4367,7 @@ EventStateManager::GenerateDragDropEnterExit(nsPresContext* aPresContext,
                             aDragEvent, NS_DRAGDROP_EXIT,
                             nullptr, lastContent, sLastDragOverFrame);
         FireDragEnterOrExit(lastDragOverFramePresContext,
-                            aDragEvent, NS_DRAGDROP_LEAVE,
+                            aDragEvent, eDragLeave,
                             nullptr, lastContent, sLastDragOverFrame);
 
         sLastDragOverFrame = nullptr;
@@ -4423,7 +4422,7 @@ EventStateManager::FireDragEnterOrExit(nsPresContext* aPresContext,
 
     // collect any changes to moz cursor settings stored in the event's
     // data transfer.
-    if (aMessage == NS_DRAGDROP_LEAVE || aMessage == NS_DRAGDROP_EXIT ||
+    if (aMessage == eDragLeave || aMessage == NS_DRAGDROP_EXIT ||
         aMessage == NS_DRAGDROP_ENTER) {
       UpdateDragDataTransfer(&event);
     }
@@ -4641,8 +4640,7 @@ already_AddRefed<nsIContent>
 EventStateManager::GetEventTargetContent(WidgetEvent* aEvent)
 {
   if (aEvent &&
-      (aEvent->mMessage == NS_FOCUS_CONTENT ||
-       aEvent->mMessage == NS_BLUR_CONTENT)) {
+      (aEvent->mMessage == eFocus || aEvent->mMessage == eBlur)) {
     nsCOMPtr<nsIContent> content = GetFocusedContent();
     return content.forget();
   }
diff --git a/dom/events/FocusEvent.cpp b/dom/events/FocusEvent.cpp
index 4f3732dcac..61b1166fed 100644
--- a/dom/events/FocusEvent.cpp
+++ b/dom/events/FocusEvent.cpp
@@ -17,7 +17,7 @@ FocusEvent::FocusEvent(EventTarget* aOwner,
                        nsPresContext* aPresContext,
                        InternalFocusEvent* aEvent)
   : UIEvent(aOwner, aPresContext,
-            aEvent ? aEvent : new InternalFocusEvent(false, NS_FOCUS_CONTENT))
+            aEvent ? aEvent : new InternalFocusEvent(false, eFocus))
 {
   if (aEvent) {
     mEventIsInternal = false;
diff --git a/dom/events/WheelHandlingHelper.cpp b/dom/events/WheelHandlingHelper.cpp
index f16eb4c975..092e90453f 100644
--- a/dom/events/WheelHandlingHelper.cpp
+++ b/dom/events/WheelHandlingHelper.cpp
@@ -214,8 +214,8 @@ WheelTransaction::OnEvent(WidgetEvent* aEvent)
     case eMouseDown:
     case eMouseDoubleClick:
     case eMouseClick:
-    case NS_CONTEXTMENU:
-    case NS_DRAGDROP_DROP:
+    case eContextMenu:
+    case eDrop:
       EndTransaction();
       return;
     default:
diff --git a/dom/fetch/InternalRequest.cpp b/dom/fetch/InternalRequest.cpp
index c4382c1a44..2baed642b1 100644
--- a/dom/fetch/InternalRequest.cpp
+++ b/dom/fetch/InternalRequest.cpp
@@ -210,8 +210,9 @@ InternalRequest::MapContentPolicyTypeToRequestContext(nsContentPolicyType aConte
   return context;
 }
 
+// static
 bool
-InternalRequest::IsNavigationRequest() const
+InternalRequest::IsNavigationContentPolicy(nsContentPolicyType aContentPolicyType)
 {
   // https://fetch.spec.whatwg.org/#navigation-request-context
   //
@@ -219,17 +220,22 @@ InternalRequest::IsNavigationRequest() const
   // "iframe", "internal" (as long as context frame type is not "none"),
   // "location", "metarefresh", and "prerender".
   //
-  // TODO: include equivalent check for "form" context
-  // TODO: include equivalent check for "prerender" context
-  return mContentPolicyType == nsIContentPolicy::TYPE_DOCUMENT ||
-         mContentPolicyType == nsIContentPolicy::TYPE_SUBDOCUMENT ||
-         mContentPolicyType == nsIContentPolicy::TYPE_INTERNAL_FRAME ||
-         mContentPolicyType == nsIContentPolicy::TYPE_INTERNAL_IFRAME ||
-         mContentPolicyType == nsIContentPolicy::TYPE_REFRESH;
+  // Note, all of these request types are effectively initiated by nsDocShell.
+  //
+  // The TYPE_REFRESH is used in some code paths for metarefresh, but will not
+  // be seen during the actual load.  Instead the new load gets a normal
+  // nsDocShell policy type.  We include it here in case this utility method
+  // is called before the load starts.
+  return aContentPolicyType == nsIContentPolicy::TYPE_DOCUMENT ||
+         aContentPolicyType == nsIContentPolicy::TYPE_SUBDOCUMENT ||
+         aContentPolicyType == nsIContentPolicy::TYPE_INTERNAL_FRAME ||
+         aContentPolicyType == nsIContentPolicy::TYPE_INTERNAL_IFRAME ||
+         aContentPolicyType == nsIContentPolicy::TYPE_REFRESH;
 }
 
+// static
 bool
-InternalRequest::IsWorkerRequest() const
+InternalRequest::IsWorkerContentPolicy(nsContentPolicyType aContentPolicyType)
 {
   // https://fetch.spec.whatwg.org/#worker-request-context
   //
@@ -239,8 +245,20 @@ InternalRequest::IsWorkerRequest() const
   // Note, service workers are not included here because currently there is
   // no way to generate a Request with a "serviceworker" RequestContext.
   // ServiceWorker scripts cannot be intercepted.
-  return mContentPolicyType == nsIContentPolicy::TYPE_INTERNAL_WORKER ||
-         mContentPolicyType == nsIContentPolicy::TYPE_INTERNAL_SHARED_WORKER;
+  return aContentPolicyType == nsIContentPolicy::TYPE_INTERNAL_WORKER ||
+         aContentPolicyType == nsIContentPolicy::TYPE_INTERNAL_SHARED_WORKER;
+}
+
+bool
+InternalRequest::IsNavigationRequest() const
+{
+  return IsNavigationContentPolicy(mContentPolicyType);
+}
+
+bool
+InternalRequest::IsWorkerRequest() const
+{
+  return IsWorkerContentPolicy(mContentPolicyType);
 }
 
 bool
@@ -249,5 +267,63 @@ InternalRequest::IsClientRequest() const
   return IsNavigationRequest() || IsWorkerRequest();
 }
 
+// static
+RequestMode
+InternalRequest::MapChannelToRequestMode(nsIChannel* aChannel)
+{
+  MOZ_ASSERT(aChannel);
+
+  nsCOMPtr<nsILoadInfo> loadInfo;
+  MOZ_ALWAYS_TRUE(NS_SUCCEEDED(aChannel->GetLoadInfo(getter_AddRefs(loadInfo))));
+
+  // RequestMode deviates from our internal security mode for navigations.
+  // While navigations normally allow cross origin we must set a same-origin
+  // RequestMode to get the correct service worker interception restrictions
+  // in place.
+  // TODO: remove the worker override once securityMode is fully implemented (bug 1189945)
+  nsContentPolicyType contentPolicy = loadInfo->InternalContentPolicyType();
+  if (IsNavigationContentPolicy(contentPolicy) ||
+      IsWorkerContentPolicy(contentPolicy)) {
+    return RequestMode::Same_origin;
+  }
+
+  uint32_t securityMode;
+  MOZ_ALWAYS_TRUE(NS_SUCCEEDED(loadInfo->GetSecurityMode(&securityMode)));
+
+  switch(securityMode) {
+    case nsILoadInfo::SEC_REQUIRE_SAME_ORIGIN_DATA_INHERITS:
+    case nsILoadInfo::SEC_REQUIRE_SAME_ORIGIN_DATA_IS_BLOCKED:
+      return RequestMode::Same_origin;
+    case nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_DATA_INHERITS:
+    case nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_DATA_IS_NULL:
+      return RequestMode::No_cors;
+    case nsILoadInfo::SEC_REQUIRE_CORS_DATA_INHERITS:
+      // TODO: Check additional flag force-preflight after bug 1199693 (bug 1189945)
+      return RequestMode::Cors;
+    default:
+      // TODO: assert never reached after CorsMode flag removed (bug 1189945)
+      MOZ_ASSERT(securityMode == nsILoadInfo::SEC_NORMAL);
+      break;
+  }
+
+  // TODO: remove following code once securityMode is fully implemented (bug 1189945)
+
+  // We only support app:// protocol interception in non-release builds.
+#ifndef RELEASE_BUILD
+  nsCOMPtr<nsIJARChannel> jarChannel = do_QueryInterface(aChannel);
+  if (jarChannel) {
+    return RequestMode::No_cors;
+  }
+#endif
+
+  nsCOMPtr<nsIHttpChannelInternal> httpChannel = do_QueryInterface(aChannel);
+
+  uint32_t corsMode;
+  MOZ_ALWAYS_TRUE(NS_SUCCEEDED(httpChannel->GetCorsMode(&corsMode)));
+
+  // This cast is valid due to static asserts in ServiceWorkerManager.cpp.
+  return static_cast<RequestMode>(corsMode);
+}
+
 } // namespace dom
 } // namespace mozilla
diff --git a/dom/fetch/InternalRequest.h b/dom/fetch/InternalRequest.h
index 9cc8aa6932..8c9d842386 100644
--- a/dom/fetch/InternalRequest.h
+++ b/dom/fetch/InternalRequest.h
@@ -377,6 +377,8 @@ public:
   bool
   IsClientRequest() const;
 
+  static RequestMode
+  MapChannelToRequestMode(nsIChannel* aChannel);
 
 private:
   // Does not copy mBodyStream.  Use fallible Clone() for complete copy.
@@ -387,6 +389,12 @@ private:
   static RequestContext
   MapContentPolicyTypeToRequestContext(nsContentPolicyType aContentPolicyType);
 
+  static bool
+  IsNavigationContentPolicy(nsContentPolicyType aContentPolicyType);
+
+  static bool
+  IsWorkerContentPolicy(nsContentPolicyType aContentPolicyType);
+
   nsCString mMethod;
   // mURL always stores the url with the ref stripped
   nsCString mURL;
diff --git a/dom/html/HTMLButtonElement.cpp b/dom/html/HTMLButtonElement.cpp
index 7e0bef9318..a5543608c5 100644
--- a/dom/html/HTMLButtonElement.cpp
+++ b/dom/html/HTMLButtonElement.cpp
@@ -227,7 +227,7 @@ HTMLButtonElement::PreHandleEvent(EventChainPreVisitor& aVisitor)
   WidgetMouseEvent* mouseEvent = aVisitor.mEvent->AsMouseEvent();
   bool outerActivateEvent =
     ((mouseEvent && mouseEvent->IsLeftClickEvent()) ||
-     (aVisitor.mEvent->mMessage == NS_UI_ACTIVATE &&
+     (aVisitor.mEvent->mMessage == eLegacyDOMActivate &&
       !mInInternalActivate));
 
   if (outerActivateEvent) {
@@ -257,7 +257,7 @@ HTMLButtonElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
     if (mouseEvent && mouseEvent->IsLeftClickEvent()) {
       // DOMActive event should be trusted since the activation is actually
       // occurred even if the cause is an untrusted click event.
-      InternalUIEvent actEvent(true, NS_UI_ACTIVATE, mouseEvent);
+      InternalUIEvent actEvent(true, eLegacyDOMActivate, mouseEvent);
       actEvent.detail = 1;
 
       nsCOMPtr<nsIPresShell> shell = aVisitor.mPresContext->GetPresShell();
@@ -359,7 +359,7 @@ HTMLButtonElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
             SetContentState(nullptr, NS_EVENT_STATE_HOVER);
           aVisitor.mEventStatus = nsEventStatus_eConsumeNoDefault;
         }
-	break;
+        break;
 
       default:
         break;
@@ -368,7 +368,7 @@ HTMLButtonElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
       if (mForm && (mType == NS_FORM_BUTTON_SUBMIT ||
                     mType == NS_FORM_BUTTON_RESET)) {
         InternalFormEvent event(true,
-          (mType == NS_FORM_BUTTON_RESET) ? NS_FORM_RESET : NS_FORM_SUBMIT);
+          (mType == NS_FORM_BUTTON_RESET) ? eFormReset : eFormSubmit);
         event.originator     = this;
         nsEventStatus status = nsEventStatus_eIgnore;
 
@@ -380,7 +380,7 @@ HTMLButtonElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
         //
         // Using presShell to dispatch the event. It makes sure that
         // event is not handled if the window is being destroyed.
-        if (presShell && (event.mMessage != NS_FORM_SUBMIT ||
+        if (presShell && (event.mMessage != eFormSubmit ||
                           mForm->HasAttr(kNameSpaceID_None, nsGkAtoms::novalidate) ||
                           // We know the element is a submit control, if this check is moved,
                           // make sure formnovalidate is used only if it's a submit control.
diff --git a/dom/html/HTMLFormElement.cpp b/dom/html/HTMLFormElement.cpp
index 3fce0b989e..f71293643f 100644
--- a/dom/html/HTMLFormElement.cpp
+++ b/dom/html/HTMLFormElement.cpp
@@ -269,7 +269,7 @@ HTMLFormElement::Submit(ErrorResult& aRv)
     mPendingSubmission = nullptr;
   }
 
-  aRv = DoSubmitOrReset(nullptr, NS_FORM_SUBMIT);
+  aRv = DoSubmitOrReset(nullptr, eFormSubmit);
 }
 
 NS_IMETHODIMP
@@ -283,7 +283,7 @@ HTMLFormElement::Submit()
 NS_IMETHODIMP
 HTMLFormElement::Reset()
 {
-  InternalFormEvent event(true, NS_FORM_RESET);
+  InternalFormEvent event(true, eFormReset);
   EventDispatcher::Dispatch(static_cast<nsIContent*>(this), nullptr, &event);
   return NS_OK;
 }
@@ -506,7 +506,7 @@ HTMLFormElement::PreHandleEvent(EventChainPreVisitor& aVisitor)
   aVisitor.mWantsWillHandleEvent = true;
   if (aVisitor.mEvent->originalTarget == static_cast<nsIContent*>(this)) {
     uint32_t msg = aVisitor.mEvent->mMessage;
-    if (msg == NS_FORM_SUBMIT) {
+    if (msg == eFormSubmit) {
       if (mGeneratingSubmit) {
         aVisitor.mCanHandle = false;
         return NS_OK;
@@ -517,8 +517,7 @@ HTMLFormElement::PreHandleEvent(EventChainPreVisitor& aVisitor)
       // that means that if there are scripted submissions, the
       // latest one will be deferred until after the exit point of the handler.
       mDeferSubmission = true;
-    }
-    else if (msg == NS_FORM_RESET) {
+    } else if (msg == eFormReset) {
       if (mGeneratingReset) {
         aVisitor.mCanHandle = false;
         return NS_OK;
@@ -535,8 +534,8 @@ HTMLFormElement::WillHandleEvent(EventChainPostVisitor& aVisitor)
   // If this is the bubble stage and there is a nested form below us which
   // received a submit event we do *not* want to handle the submit event
   // for this form too.
-  if ((aVisitor.mEvent->mMessage == NS_FORM_SUBMIT ||
-       aVisitor.mEvent->mMessage == NS_FORM_RESET) &&
+  if ((aVisitor.mEvent->mMessage == eFormSubmit ||
+       aVisitor.mEvent->mMessage == eFormReset) &&
       aVisitor.mEvent->mFlags.mInBubblingPhase &&
       aVisitor.mEvent->originalTarget != static_cast<nsIContent*>(this)) {
     aVisitor.mEvent->mFlags.mPropagationStopped = true;
@@ -549,17 +548,16 @@ HTMLFormElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
 {
   if (aVisitor.mEvent->originalTarget == static_cast<nsIContent*>(this)) {
     EventMessage msg = aVisitor.mEvent->mMessage;
-    if (msg == NS_FORM_SUBMIT) {
+    if (msg == eFormSubmit) {
       // let the form know not to defer subsequent submissions
       mDeferSubmission = false;
     }
 
     if (aVisitor.mEventStatus == nsEventStatus_eIgnore) {
       switch (msg) {
-        case NS_FORM_RESET:
-        case NS_FORM_SUBMIT:
-        {
-          if (mPendingSubmission && msg == NS_FORM_SUBMIT) {
+        case eFormReset:
+        case eFormSubmit: {
+          if (mPendingSubmission && msg == eFormSubmit) {
             // tell the form to forget a possible pending submission.
             // the reason is that the script returned true (the event was
             // ignored) so if there is a stored submission, it will miss
@@ -574,7 +572,7 @@ HTMLFormElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
           break;
       }
     } else {
-      if (msg == NS_FORM_SUBMIT) {
+      if (msg == eFormSubmit) {
         // tell the form to flush a possible pending submission.
         // the reason is that the script returned false (the event was
         // not ignored) so if there is a stored submission, it needs to
@@ -583,10 +581,9 @@ HTMLFormElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
       }
     }
 
-    if (msg == NS_FORM_SUBMIT) {
+    if (msg == eFormSubmit) {
       mGeneratingSubmit = false;
-    }
-    else if (msg == NS_FORM_RESET) {
+    } else if (msg == eFormReset) {
       mGeneratingReset = false;
     }
   }
@@ -595,7 +592,7 @@ HTMLFormElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
 
 nsresult
 HTMLFormElement::DoSubmitOrReset(WidgetEvent* aEvent,
-                                 int32_t aMessage)
+                                 EventMessage aMessage)
 {
   // Make sure the presentation is up-to-date
   nsIDocument* doc = GetComposedDoc();
@@ -606,11 +603,11 @@ HTMLFormElement::DoSubmitOrReset(WidgetEvent* aEvent,
   // JBK Don't get form frames anymore - bug 34297
 
   // Submit or Reset the form
-  if (NS_FORM_RESET == aMessage) {
+  if (eFormReset == aMessage) {
     return DoReset();
   }
 
-  if (NS_FORM_SUBMIT == aMessage) {
+  if (eFormSubmit == aMessage) {
     // Don't submit if we're not in a document or if we're in
     // a sandboxed frame and form submit is disabled.
     if (!doc || (doc->GetSandboxFlags() & SANDBOXED_FORMS)) {
diff --git a/dom/html/HTMLFormElement.h b/dom/html/HTMLFormElement.h
index 26b688d029..f577b11bba 100644
--- a/dom/html/HTMLFormElement.h
+++ b/dom/html/HTMLFormElement.h
@@ -452,7 +452,7 @@ protected:
   };
 
   nsresult DoSubmitOrReset(WidgetEvent* aEvent,
-                           int32_t aMessage);
+                           EventMessage aMessage);
   nsresult DoReset();
 
   // Async callback to handle removal of our default submit
diff --git a/dom/html/HTMLInputElement.cpp b/dom/html/HTMLInputElement.cpp
index 9a2d606a74..245307b1c3 100644
--- a/dom/html/HTMLInputElement.cpp
+++ b/dom/html/HTMLInputElement.cpp
@@ -2809,7 +2809,7 @@ HTMLInputElement::MaybeSubmitForm(nsPresContext* aPresContext)
     // If there's only one text control, just submit the form
     // Hold strong ref across the event
     nsRefPtr<mozilla::dom::HTMLFormElement> form = mForm;
-    InternalFormEvent event(true, NS_FORM_SUBMIT);
+    InternalFormEvent event(true, eFormSubmit);
     nsEventStatus status = nsEventStatus_eIgnore;
     shell->HandleDOMEventWithTarget(mForm, &event, &status);
   }
@@ -2980,7 +2980,7 @@ HTMLInputElement::DispatchSelectEvent(nsPresContext* aPresContext)
 
   // If already handling select event, don't dispatch a second.
   if (!mHandlingSelectEvent) {
-    WidgetEvent event(nsContentUtils::IsCallerChrome(), NS_FORM_SELECTED);
+    WidgetEvent event(nsContentUtils::IsCallerChrome(), eFormSelect);
 
     mHandlingSelectEvent = true;
     EventDispatcher::Dispatch(static_cast<nsIContent*>(this),
@@ -3080,7 +3080,7 @@ HTMLInputElement::PreHandleEvent(EventChainPreVisitor& aVisitor)
   WidgetMouseEvent* mouseEvent = aVisitor.mEvent->AsMouseEvent();
   bool outerActivateEvent =
     ((mouseEvent && mouseEvent->IsLeftClickEvent()) ||
-     (aVisitor.mEvent->mMessage == NS_UI_ACTIVATE && !mInInternalActivate));
+     (aVisitor.mEvent->mMessage == eLegacyDOMActivate && !mInInternalActivate));
 
   if (outerActivateEvent) {
     aVisitor.mItemFlags |= NS_OUTER_ACTIVATE_EVENT;
@@ -3155,7 +3155,7 @@ HTMLInputElement::PreHandleEvent(EventChainPreVisitor& aVisitor)
   aVisitor.mItemFlags |= mType;
 
   // Fire onchange (if necessary), before we do the blur, bug 357684.
-  if (aVisitor.mEvent->mMessage == NS_BLUR_CONTENT) {
+  if (aVisitor.mEvent->mMessage == eBlur) {
     // Experimental mobile types rely on the system UI to prevent users to not
     // set invalid values but we have to be extra-careful. Especially if the
     // option has been enabled on desktop.
@@ -3169,8 +3169,8 @@ HTMLInputElement::PreHandleEvent(EventChainPreVisitor& aVisitor)
   }
 
   if (mType == NS_FORM_INPUT_RANGE &&
-      (aVisitor.mEvent->mMessage == NS_FOCUS_CONTENT ||
-       aVisitor.mEvent->mMessage == NS_BLUR_CONTENT)) {
+      (aVisitor.mEvent->mMessage == eFocus ||
+       aVisitor.mEvent->mMessage == eBlur)) {
     // Just as nsGenericHTMLFormElementWithState::PreHandleEvent calls
     // nsIFormControlFrame::SetFocus, we handle focus here.
     nsIFrame* frame = GetPrimaryFrame();
@@ -3223,9 +3223,9 @@ HTMLInputElement::PreHandleEvent(EventChainPreVisitor& aVisitor)
         StopNumberControlSpinnerSpin();
       }
     }
-    if (aVisitor.mEvent->mMessage == NS_FOCUS_CONTENT ||
-        aVisitor.mEvent->mMessage == NS_BLUR_CONTENT) {
-      if (aVisitor.mEvent->mMessage == NS_FOCUS_CONTENT) {
+    if (aVisitor.mEvent->mMessage == eFocus ||
+        aVisitor.mEvent->mMessage == eBlur) {
+      if (aVisitor.mEvent->mMessage == eFocus) {
         // Tell our frame it's getting focus so that it can make sure focus
         // is moved to our anonymous text control.
         nsNumberControlFrame* numberControlFrame =
@@ -3289,7 +3289,7 @@ HTMLInputElement::PreHandleEvent(EventChainPreVisitor& aVisitor)
           numberControlFrame->HandlingInputEvent(false);
         }
       }
-      else if (aVisitor.mEvent->mMessage == NS_FORM_CHANGE) {
+      else if (aVisitor.mEvent->mMessage == eFormChange) {
         // We cancel the DOM 'change' event that is fired for any change to our
         // anonymous text control since we fire our own 'change' events and
         // content shouldn't be seeing two 'change' events. Besides that we
@@ -3576,15 +3576,15 @@ HTMLInputElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
     return MaybeInitPickers(aVisitor);
   }
 
-  if (aVisitor.mEvent->mMessage == NS_FOCUS_CONTENT ||
-      aVisitor.mEvent->mMessage == NS_BLUR_CONTENT) {
-    if (aVisitor.mEvent->mMessage == NS_FOCUS_CONTENT &&
+  if (aVisitor.mEvent->mMessage == eFocus ||
+      aVisitor.mEvent->mMessage == eBlur) {
+    if (aVisitor.mEvent->mMessage == eFocus &&
         MayFireChangeOnBlur() &&
         !mIsDraggingRange) { // StartRangeThumbDrag already set mFocusedValue
       GetValue(mFocusedValue);
     }
 
-    if (aVisitor.mEvent->mMessage == NS_BLUR_CONTENT) {
+    if (aVisitor.mEvent->mMessage == eBlur) {
       if (mIsDraggingRange) {
         FinishRangeThumbDrag();
       } else if (mNumberControlSpinnerIsSpinning) {
@@ -3592,7 +3592,7 @@ HTMLInputElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
       }
     }
 
-    UpdateValidityUIBits(aVisitor.mEvent->mMessage == NS_FOCUS_CONTENT);
+    UpdateValidityUIBits(aVisitor.mEvent->mMessage == eFocus);
 
     UpdateState(true);
   }
@@ -3619,7 +3619,7 @@ HTMLInputElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
         !ShouldPreventDOMActivateDispatch(aVisitor.mEvent->originalTarget)) {
       // DOMActive event should be trusted since the activation is actually
       // occurred even if the cause is an untrusted click event.
-      InternalUIEvent actEvent(true, NS_UI_ACTIVATE, mouseEvent);
+      InternalUIEvent actEvent(true, eLegacyDOMActivate, mouseEvent);
       actEvent.detail = 1;
 
       nsCOMPtr<nsIPresShell> shell = aVisitor.mPresContext->GetPresShell();
@@ -3734,9 +3734,7 @@ HTMLInputElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
       }
     } else if (nsEventStatus_eIgnore == aVisitor.mEventStatus) {
       switch (aVisitor.mEvent->mMessage) {
-
-        case NS_FOCUS_CONTENT:
-        {
+        case eFocus: {
           // see if we should select the contents of the textbox. This happens
           // for text and password fields when the field was focused by the
           // keyboard or a navigation, the platform allows it, and it wasn't
@@ -3991,7 +3989,7 @@ HTMLInputElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
         case NS_FORM_INPUT_IMAGE:
           if (mForm) {
             InternalFormEvent event(true,
-              (mType == NS_FORM_INPUT_RESET) ? NS_FORM_RESET : NS_FORM_SUBMIT);
+              (mType == NS_FORM_INPUT_RESET) ? eFormReset : eFormSubmit);
             event.originator      = this;
             nsEventStatus status  = nsEventStatus_eIgnore;
 
@@ -4003,7 +4001,7 @@ HTMLInputElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
             // pres shell.  See bug 125624.
             // TODO: removing this code and have the submit event sent by the
             // form, see bug 592124.
-            if (presShell && (event.mMessage != NS_FORM_SUBMIT ||
+            if (presShell && (event.mMessage != eFormSubmit ||
                               mForm->HasAttr(kNameSpaceID_None, nsGkAtoms::novalidate) ||
                               // We know the element is a submit control, if this check is moved,
                               // make sure formnovalidate is used only if it's a submit control.
diff --git a/dom/html/HTMLObjectElement.cpp b/dom/html/HTMLObjectElement.cpp
index 31647430dc..5f918d05d3 100644
--- a/dom/html/HTMLObjectElement.cpp
+++ b/dom/html/HTMLObjectElement.cpp
@@ -211,11 +211,11 @@ HTMLObjectElement::HandleFocusBlurPlugin(Element* aElement,
     return;
   }
   switch (aEvent->mMessage) {
-    case NS_FOCUS_CONTENT: {
+    case eFocus: {
       OnFocusBlurPlugin(aElement, true);
       break;
     }
-    case NS_BLUR_CONTENT: {
+    case eBlur: {
       OnFocusBlurPlugin(aElement, false);
       break;
     }
@@ -287,7 +287,7 @@ HTMLObjectElement::UnbindFromTree(bool aDeep,
 {
 #ifdef XP_MACOSX
   // When a page is reloaded (when an nsIDocument's content is removed), the
-  // focused element isn't necessarily sent an NS_BLUR_CONTENT event. See
+  // focused element isn't necessarily sent an eBlur event. See
   // nsFocusManager::ContentRemoved(). This means that a widget may think it
   // still contains a focused plugin when it doesn't -- which in turn can
   // disable text input in the browser window. See bug 1137229.
diff --git a/dom/html/HTMLSelectElement.cpp b/dom/html/HTMLSelectElement.cpp
index 1f8cc1a81e..89208c6cad 100644
--- a/dom/html/HTMLSelectElement.cpp
+++ b/dom/html/HTMLSelectElement.cpp
@@ -1520,7 +1520,7 @@ HTMLSelectElement::PreHandleEvent(EventChainPreVisitor& aVisitor)
 nsresult
 HTMLSelectElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
 {
-  if (aVisitor.mEvent->mMessage == NS_FOCUS_CONTENT) {
+  if (aVisitor.mEvent->mMessage == eFocus) {
     // If the invalid UI is shown, we should show it while focused and
     // update the invalid/valid UI.
     mCanShowInvalidUI = !IsValid() && ShouldShowValidityUI();
@@ -1531,7 +1531,7 @@ HTMLSelectElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
 
     // We don't have to update NS_EVENT_STATE_MOZ_UI_INVALID nor
     // NS_EVENT_STATE_MOZ_UI_VALID given that the states should not change.
-  } else if (aVisitor.mEvent->mMessage == NS_BLUR_CONTENT) {
+  } else if (aVisitor.mEvent->mMessage == eBlur) {
     mCanShowInvalidUI = true;
     mCanShowValidUI = true;
 
diff --git a/dom/html/HTMLSharedObjectElement.cpp b/dom/html/HTMLSharedObjectElement.cpp
index a7679d2be9..bb2df743db 100644
--- a/dom/html/HTMLSharedObjectElement.cpp
+++ b/dom/html/HTMLSharedObjectElement.cpp
@@ -164,7 +164,7 @@ HTMLSharedObjectElement::UnbindFromTree(bool aDeep,
 {
 #ifdef XP_MACOSX
   // When a page is reloaded (when an nsIDocument's content is removed), the
-  // focused element isn't necessarily sent an NS_BLUR_CONTENT event. See
+  // focused element isn't necessarily sent an eBlur event. See
   // nsFocusManager::ContentRemoved(). This means that a widget may think it
   // still contains a focused plugin when it doesn't -- which in turn can
   // disable text input in the browser window. See bug 1137229.
diff --git a/dom/html/HTMLTextAreaElement.cpp b/dom/html/HTMLTextAreaElement.cpp
index eca1d6bcdf..1ccd24e171 100644
--- a/dom/html/HTMLTextAreaElement.cpp
+++ b/dom/html/HTMLTextAreaElement.cpp
@@ -137,7 +137,7 @@ HTMLTextAreaElement::Select()
   }
 
   nsEventStatus status = nsEventStatus_eIgnore;
-  WidgetGUIEvent event(true, NS_FORM_SELECTED, nullptr);
+  WidgetGUIEvent event(true, eFormSelect, nullptr);
   // XXXbz HTMLInputElement guards against this reentering; shouldn't we?
   EventDispatcher::Dispatch(static_cast<nsIContent*>(this), presContext,
                             &event, nullptr, &status);
@@ -484,7 +484,7 @@ HTMLTextAreaElement::PreHandleEvent(EventChainPreVisitor& aVisitor)
 
   // Don't dispatch a second select event if we are already handling
   // one.
-  if (aVisitor.mEvent->mMessage == NS_FORM_SELECTED) {
+  if (aVisitor.mEvent->mMessage == eFormSelect) {
     if (mHandlingSelect) {
       return NS_OK;
     }
@@ -504,7 +504,7 @@ HTMLTextAreaElement::PreHandleEvent(EventChainPreVisitor& aVisitor)
   }
 
   // Fire onchange (if necessary), before we do the blur, bug 370521.
-  if (aVisitor.mEvent->mMessage == NS_BLUR_CONTENT) {
+  if (aVisitor.mEvent->mMessage == eBlur) {
     FireChangeEventIfNeeded();
   }
 
@@ -532,13 +532,13 @@ HTMLTextAreaElement::FireChangeEventIfNeeded()
 nsresult
 HTMLTextAreaElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
 {
-  if (aVisitor.mEvent->mMessage == NS_FORM_SELECTED) {
+  if (aVisitor.mEvent->mMessage == eFormSelect) {
     mHandlingSelect = false;
   }
 
-  if (aVisitor.mEvent->mMessage == NS_FOCUS_CONTENT ||
-      aVisitor.mEvent->mMessage == NS_BLUR_CONTENT) {
-    if (aVisitor.mEvent->mMessage == NS_FOCUS_CONTENT) {
+  if (aVisitor.mEvent->mMessage == eFocus ||
+      aVisitor.mEvent->mMessage == eBlur) {
+    if (aVisitor.mEvent->mMessage == eFocus) {
       // If the invalid UI is shown, we should show it while focusing (and
       // update). Otherwise, we should not.
       GetValueInternal(mFocusedValue, true);
@@ -547,7 +547,7 @@ HTMLTextAreaElement::PostHandleEvent(EventChainPostVisitor& aVisitor)
       // If neither invalid UI nor valid UI is shown, we shouldn't show the valid
       // UI while typing.
       mCanShowValidUI = ShouldShowValidityUI();
-    } else { // NS_BLUR_CONTENT
+    } else { // eBlur
       mCanShowInvalidUI = true;
       mCanShowValidUI = true;
     }
diff --git a/dom/html/nsGenericHTMLElement.cpp b/dom/html/nsGenericHTMLElement.cpp
index 0a9b771247..ea930d9750 100644
--- a/dom/html/nsGenericHTMLElement.cpp
+++ b/dom/html/nsGenericHTMLElement.cpp
@@ -2252,8 +2252,7 @@ nsGenericHTMLFormElement::PreHandleEvent(EventChainPreVisitor& aVisitor)
 {
   if (aVisitor.mEvent->mFlags.mIsTrusted) {
     switch (aVisitor.mEvent->mMessage) {
-      case NS_FOCUS_CONTENT:
-      {
+      case eFocus: {
         // Check to see if focus has bubbled up from a form control's
         // child textfield or button.  If that's the case, don't focus
         // this parent file control -- leave focus on the child.
@@ -2263,8 +2262,7 @@ nsGenericHTMLFormElement::PreHandleEvent(EventChainPreVisitor& aVisitor)
           formControlFrame->SetFocus(true, true);
         break;
       }
-      case NS_BLUR_CONTENT:
-      {
+      case eBlur: {
         nsIFormControlFrame* formControlFrame = GetFormControlFrame(true);
         if (formControlFrame)
           formControlFrame->SetFocus(false, false);
@@ -2454,10 +2452,10 @@ nsGenericHTMLFormElement::IsElementDisabledForEvents(EventMessage aMessage,
     case eMouseOut:
     case eMouseEnter:
     case eMouseLeave:
-    case NS_POINTER_MOVE:
-    case NS_POINTER_OVER:
-    case NS_POINTER_OUT:
-    case NS_POINTER_ENTER:
+    case ePointerMove:
+    case ePointerOver:
+    case ePointerOut:
+    case ePointerEnter:
     case ePointerLeave:
     case NS_WHEEL_WHEEL:
     case NS_MOUSE_SCROLL:
diff --git a/dom/html/nsTextEditorState.cpp b/dom/html/nsTextEditorState.cpp
index 439c5051c9..799a43ec42 100644
--- a/dom/html/nsTextEditorState.cpp
+++ b/dom/html/nsTextEditorState.cpp
@@ -822,7 +822,7 @@ nsTextInputListener::NotifySelectionChanged(nsIDOMDocument* aDoc, nsISelection*
         if (presShell) 
         {
           nsEventStatus status = nsEventStatus_eIgnore;
-          WidgetEvent event(true, NS_FORM_SELECTED);
+          WidgetEvent event(true, eFormSelect);
 
           presShell->HandleEventWithTarget(&event, mFrame, content, &status);
         }
diff --git a/dom/ipc/ContentChild.cpp b/dom/ipc/ContentChild.cpp
index 23a1680011..ebf14e3caf 100644
--- a/dom/ipc/ContentChild.cpp
+++ b/dom/ipc/ContentChild.cpp
@@ -2819,7 +2819,7 @@ ContentChild::RecvInvokeDragSession(nsTArray<IPCDataTransfer>&& aTransfers,
     if (session) {
       session->SetDragAction(aAction);
       nsCOMPtr<DataTransfer> dataTransfer =
-        new DataTransfer(nullptr, NS_DRAGDROP_START, false, -1);
+        new DataTransfer(nullptr, eDragStart, false, -1);
       for (uint32_t i = 0; i < aTransfers.Length(); ++i) {
         auto& items = aTransfers[i].items();
         for (uint32_t j = 0; j < items.Length(); ++j) {
diff --git a/dom/ipc/ContentParent.cpp b/dom/ipc/ContentParent.cpp
index c58188a259..cb97c9616c 100755
--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -5114,9 +5114,9 @@ ContentParent::MaybeInvokeDragSession(TabParent* aParent)
       session->GetDataTransfer(getter_AddRefs(domTransfer));
       nsCOMPtr<DataTransfer> transfer = do_QueryInterface(domTransfer);
       if (!transfer) {
-        // Pass NS_DRAGDROP_DROP to get DataTransfer with external
+        // Pass eDrop to get DataTransfer with external
         // drag formats cached.
-        transfer = new DataTransfer(nullptr, NS_DRAGDROP_DROP, true, -1);
+        transfer = new DataTransfer(nullptr, eDrop, true, -1);
         session->SetDataTransfer(transfer);
       }
       // Note, even though this fills the DataTransfer object with
diff --git a/dom/ipc/TabChild.cpp b/dom/ipc/TabChild.cpp
index 7a380dfebe..b3a045c242 100644
--- a/dom/ipc/TabChild.cpp
+++ b/dom/ipc/TabChild.cpp
@@ -2194,7 +2194,7 @@ TabChild::RecvRealDragEvent(const WidgetDragEvent& aEvent,
     }
   }
 
-  if (aEvent.mMessage == NS_DRAGDROP_DROP) {
+  if (aEvent.mMessage == eDrop) {
     bool canDrop = true;
     if (!dragSession || NS_FAILED(dragSession->GetCanDrop(&canDrop)) ||
         !canDrop) {
diff --git a/dom/plugins/base/nsPluginInstanceOwner.cpp b/dom/plugins/base/nsPluginInstanceOwner.cpp
index a107046f07..7daef459ff 100644
--- a/dom/plugins/base/nsPluginInstanceOwner.cpp
+++ b/dom/plugins/base/nsPluginInstanceOwner.cpp
@@ -1686,7 +1686,7 @@ nsPluginInstanceOwner::HandleEvent(nsIDOMEvent* aEvent)
   }
   if (eventType.EqualsLiteral("MozPerformDelayedBlur")) {
     if (mShouldBlurOnActivate) {
-      WidgetGUIEvent blurEvent(true, NS_BLUR_CONTENT, nullptr);
+      WidgetGUIEvent blurEvent(true, eBlur, nullptr);
       ProcessEvent(blurEvent);
       mShouldBlurOnActivate = false;
     }
@@ -1810,8 +1810,8 @@ CocoaEventTypeForEvent(const WidgetGUIEvent& anEvent, nsIFrame* aObjectFrame)
       return NPCocoaEventKeyDown;
     case eKeyUp:
       return NPCocoaEventKeyUp;
-    case NS_FOCUS_CONTENT:
-    case NS_BLUR_CONTENT:
+    case eFocus:
+    case eBlur:
       return NPCocoaEventFocusChanged;
     case NS_MOUSE_SCROLL:
       return NPCocoaEventScrollWheel;
@@ -1915,9 +1915,9 @@ TranslateToNPCocoaEvent(WidgetGUIEvent* anEvent, nsIFrame* aObjectFrame)
       }
       break;
     }
-    case NS_FOCUS_CONTENT:
-    case NS_BLUR_CONTENT:
-      cocoaEvent.data.focus.hasFocus = (anEvent->mMessage == NS_FOCUS_CONTENT);
+    case eFocus:
+    case eBlur:
+      cocoaEvent.data.focus.hasFocus = (anEvent->mMessage == eFocus);
       break;
     default:
       break;
@@ -1955,8 +1955,7 @@ nsEventStatus nsPluginInstanceOwner::ProcessEvent(const WidgetGUIEvent& anEvent)
   // focus unless it lost focus within the window. For example, ignore a blur
   // event if it's coming due to the plugin's window deactivating.
   nsCOMPtr<nsIContent> content = do_QueryReferent(mContent);
-  if (anEvent.mMessage == NS_BLUR_CONTENT &&
-      ContentIsFocusedWithinWindow(content)) {
+  if (anEvent.mMessage == eBlur && ContentIsFocusedWithinWindow(content)) {
     mShouldBlurOnActivate = true;
     return nsEventStatus_eIgnore;
   }
@@ -1965,8 +1964,7 @@ nsEventStatus nsPluginInstanceOwner::ProcessEvent(const WidgetGUIEvent& anEvent)
   // it focus. This might happen if it has focus, its window is blurred, then the
   // window is made active again. The plugin never lost in-window focus, so it
   // shouldn't get a focus event again.
-  if (anEvent.mMessage == NS_FOCUS_CONTENT &&
-      mLastContentFocused == true) {
+  if (anEvent.mMessage == eFocus && mLastContentFocused == true) {
     mShouldBlurOnActivate = false;
     return nsEventStatus_eIgnore;
   }
@@ -1974,9 +1972,8 @@ nsEventStatus nsPluginInstanceOwner::ProcessEvent(const WidgetGUIEvent& anEvent)
   // Now, if we're going to send a focus event, update mLastContentFocused and
   // tell any plugins in our window that we have taken focus, so they should
   // perform any delayed blurs.
-  if (anEvent.mMessage == NS_FOCUS_CONTENT ||
-      anEvent.mMessage == NS_BLUR_CONTENT) {
-    mLastContentFocused = (anEvent.mMessage == NS_FOCUS_CONTENT);
+  if (anEvent.mMessage == eFocus || anEvent.mMessage == eBlur) {
+    mLastContentFocused = (anEvent.mMessage == eFocus);
     mShouldBlurOnActivate = false;
     PerformDelayedBlurs();
   }
@@ -2103,13 +2100,13 @@ nsEventStatus nsPluginInstanceOwner::ProcessEvent(const WidgetGUIEvent& anEvent)
   }
   else if (!pPluginEvent) {
     switch (anEvent.mMessage) {
-      case NS_FOCUS_CONTENT:
+      case eFocus:
         pluginEvent.event = WM_SETFOCUS;
         pluginEvent.wParam = 0;
         pluginEvent.lParam = 0;
         pPluginEvent = &pluginEvent;
         break;
-      case NS_BLUR_CONTENT:
+      case eBlur:
         pluginEvent.event = WM_KILLFOCUS;
         pluginEvent.wParam = 0;
         pluginEvent.lParam = 0;
@@ -2302,12 +2299,11 @@ nsEventStatus nsPluginInstanceOwner::ProcessEvent(const WidgetGUIEvent& anEvent)
 
     default:
       switch (anEvent.mMessage) {
-        case NS_FOCUS_CONTENT:
-        case NS_BLUR_CONTENT:
+        case eFocus:
+        case eBlur:
           {
             XFocusChangeEvent &event = pluginEvent.xfocus;
-            event.type =
-              anEvent.mMessage == NS_FOCUS_CONTENT ? FocusIn : FocusOut;
+            event.type = anEvent.mMessage == eFocus ? FocusIn : FocusOut;
             // information lost:
             event.mode = -1;
             event.detail = NotifyDetailNone;
diff --git a/dom/workers/ServiceWorkerEvents.cpp b/dom/workers/ServiceWorkerEvents.cpp
index 3cfb4899c3..fef9967292 100644
--- a/dom/workers/ServiceWorkerEvents.cpp
+++ b/dom/workers/ServiceWorkerEvents.cpp
@@ -150,7 +150,7 @@ class RespondWithHandler final : public PromiseNativeHandler
   nsMainThreadPtrHandle<nsIInterceptedChannel> mInterceptedChannel;
   nsMainThreadPtrHandle<ServiceWorker> mServiceWorker;
   const RequestMode mRequestMode;
-  const bool mIsClientRequest;
+  const DebugOnly<bool> mIsClientRequest;
   const bool mIsNavigationRequest;
 public:
   NS_DECL_ISUPPORTS
@@ -271,8 +271,6 @@ RespondWithHandler::ResolvedCallback(JSContext* aCx, JS::Handle<JS::Value> aValu
   //  If one of the following conditions is true, return a network error:
   //    * response's type is "error".
   //    * request's mode is not "no-cors" and response's type is "opaque".
-  //    * request is a client request and response's type is neither "basic"
-  //      nor "default".
   //    * request is not a navigation request and response's type is
   //      "opaqueredirect".
 
@@ -281,19 +279,13 @@ RespondWithHandler::ResolvedCallback(JSContext* aCx, JS::Handle<JS::Value> aValu
     return;
   }
 
+  MOZ_ASSERT_IF(mIsClientRequest, mRequestMode == RequestMode::Same_origin);
+
   if (response->Type() == ResponseType::Opaque && mRequestMode != RequestMode::No_cors) {
     autoCancel.SetCancelStatus(NS_ERROR_BAD_OPAQUE_INTERCEPTION_REQUEST_MODE);
     return;
   }
 
-  // TODO: remove this case as its no longer in the spec (bug 1184967)
-  if (mIsClientRequest && response->Type() != ResponseType::Basic &&
-      response->Type() != ResponseType::Default &&
-      response->Type() != ResponseType::Opaqueredirect) {
-    autoCancel.SetCancelStatus(NS_ERROR_CLIENT_REQUEST_OPAQUE_INTERCEPTION);
-    return;
-  }
-
   if (!mIsNavigationRequest && response->Type() == ResponseType::Opaqueredirect) {
     autoCancel.SetCancelStatus(NS_ERROR_BAD_OPAQUE_REDIRECT_INTERCEPTION);
     return;
diff --git a/dom/workers/ServiceWorkerManager.cpp b/dom/workers/ServiceWorkerManager.cpp
index 1da07085d2..5f201853f2 100644
--- a/dom/workers/ServiceWorkerManager.cpp
+++ b/dom/workers/ServiceWorkerManager.cpp
@@ -3714,22 +3714,7 @@ public:
       nsCOMPtr<nsIHttpChannelInternal> internalChannel = do_QueryInterface(httpChannel);
       NS_ENSURE_TRUE(internalChannel, NS_ERROR_NOT_AVAILABLE);
 
-      uint32_t corsMode;
-      internalChannel->GetCorsMode(&corsMode);
-      switch (corsMode) {
-        case nsIHttpChannelInternal::CORS_MODE_SAME_ORIGIN:
-          mRequestMode = RequestMode::Same_origin;
-          break;
-        case nsIHttpChannelInternal::CORS_MODE_NO_CORS:
-          mRequestMode = RequestMode::No_cors;
-          break;
-        case nsIHttpChannelInternal::CORS_MODE_CORS:
-        case nsIHttpChannelInternal::CORS_MODE_CORS_WITH_FORCED_PREFLIGHT:
-          mRequestMode = RequestMode::Cors;
-          break;
-        default:
-          MOZ_CRASH("Unexpected CORS mode");
-      }
+      mRequestMode = InternalRequest::MapChannelToRequestMode(channel);
 
       // This is safe due to static_asserts at top of file.
       uint32_t redirectMode;
@@ -3762,6 +3747,8 @@ public:
 
       mMethod = "GET";
 
+      mRequestMode = InternalRequest::MapChannelToRequestMode(channel);
+
       if (loadFlags & nsIRequest::LOAD_ANONYMOUS) {
         mRequestCredentials = RequestCredentials::Omit;
       }
diff --git a/dom/workers/test/serviceworkers/fetch/origin/https/origin_test.js b/dom/workers/test/serviceworkers/fetch/origin/https/origin_test.js
index cf9bdae973..ddbf02d4c6 100644
--- a/dom/workers/test/serviceworkers/fetch/origin/https/origin_test.js
+++ b/dom/workers/test/serviceworkers/fetch/origin/https/origin_test.js
@@ -4,8 +4,7 @@ self.addEventListener("install", function(event) {
   event.waitUntil(
     self.caches.open("origin-cache")
       .then(c => {
-        return c.add(new Request(prefix + 'index-https.sjs',
-                                 { redirect: 'manual' }));
+        return c.add(prefix + 'index-https.sjs');
       })
   );
 });
diff --git a/dom/workers/test/serviceworkers/fetch/origin/https/realindex.html^headers^ b/dom/workers/test/serviceworkers/fetch/origin/https/realindex.html^headers^
new file mode 100644
index 0000000000..5ed82fd065
--- /dev/null
+++ b/dom/workers/test/serviceworkers/fetch/origin/https/realindex.html^headers^
@@ -0,0 +1 @@
+Access-Control-Allow-Origin: https://example.com
diff --git a/dom/workers/test/serviceworkers/fetch/origin/origin_test.js b/dom/workers/test/serviceworkers/fetch/origin/origin_test.js
index a68dac0eca..c9ef3ac0d5 100644
--- a/dom/workers/test/serviceworkers/fetch/origin/origin_test.js
+++ b/dom/workers/test/serviceworkers/fetch/origin/origin_test.js
@@ -6,10 +6,8 @@ self.addEventListener("install", function(event) {
       .then(c => {
         return Promise.all(
           [
-            c.add(new Request(prefix + 'index.sjs',
-                              { redirect: 'manual' } )),
-            c.add(new Request(prefix + 'index-to-https.sjs',
-                              { redirect: 'manual' } ))
+            c.add(prefix + 'index.sjs'),
+            c.add(prefix + 'index-to-https.sjs')
           ]
         );
       })
diff --git a/dom/workers/test/serviceworkers/fetch/origin/realindex.html^headers^ b/dom/workers/test/serviceworkers/fetch/origin/realindex.html^headers^
new file mode 100644
index 0000000000..3a6a85d894
--- /dev/null
+++ b/dom/workers/test/serviceworkers/fetch/origin/realindex.html^headers^
@@ -0,0 +1 @@
+Access-Control-Allow-Origin: http://mochi.test:8888
diff --git a/dom/workers/test/serviceworkers/mochitest.ini b/dom/workers/test/serviceworkers/mochitest.ini
index f3d928b421..aaa955898c 100644
--- a/dom/workers/test/serviceworkers/mochitest.ini
+++ b/dom/workers/test/serviceworkers/mochitest.ini
@@ -54,11 +54,13 @@ support-files =
   fetch/origin/index.sjs
   fetch/origin/index-to-https.sjs
   fetch/origin/realindex.html
+  fetch/origin/realindex.html^headers^
   fetch/origin/register.html
   fetch/origin/unregister.html
   fetch/origin/origin_test.js
   fetch/origin/https/index-https.sjs
   fetch/origin/https/realindex.html
+  fetch/origin/https/realindex.html^headers^
   fetch/origin/https/register.html
   fetch/origin/https/unregister.html
   fetch/origin/https/origin_test.js
diff --git a/dom/xml/XMLDocument.cpp b/dom/xml/XMLDocument.cpp
index d39bf35011..d93a782fc8 100644
--- a/dom/xml/XMLDocument.cpp
+++ b/dom/xml/XMLDocument.cpp
@@ -583,7 +583,7 @@ XMLDocument::EndLoad()
     // Generate a document load event for the case when an XML
     // document was loaded as pure data without any presentation
     // attached to it.
-    WidgetEvent event(true, NS_LOAD);
+    WidgetEvent event(true, eLoad);
     EventDispatcher::Dispatch(static_cast<nsIDocument*>(this), nullptr, &event);
   }
 }
diff --git a/dom/xul/nsXULElement.cpp b/dom/xul/nsXULElement.cpp
index 7c05acf002..339fc67d18 100644
--- a/dom/xul/nsXULElement.cpp
+++ b/dom/xul/nsXULElement.cpp
@@ -1277,8 +1277,8 @@ nsXULElement::PreHandleEvent(EventChainPreVisitor& aVisitor)
         (aVisitor.mEvent->mMessage == eMouseClick ||
          aVisitor.mEvent->mMessage == eMouseDoubleClick ||
          aVisitor.mEvent->mMessage == NS_XUL_COMMAND ||
-         aVisitor.mEvent->mMessage == NS_CONTEXTMENU ||
-         aVisitor.mEvent->mMessage == NS_DRAGDROP_START ||
+         aVisitor.mEvent->mMessage == eContextMenu ||
+         aVisitor.mEvent->mMessage == eDragStart ||
          aVisitor.mEvent->mMessage == NS_DRAGDROP_GESTURE)) {
         // Don't propagate these events from native anonymous scrollbar.
         aVisitor.mCanHandle = true;
diff --git a/editor/libeditor/nsEditorEventListener.cpp b/editor/libeditor/nsEditorEventListener.cpp
index 9644378c10..544cfe7cea 100644
--- a/editor/libeditor/nsEditorEventListener.cpp
+++ b/editor/libeditor/nsEditorEventListener.cpp
@@ -386,7 +386,7 @@ nsEditorEventListener::HandleEvent(nsIDOMEvent* aEvent)
       return DragExit(dragEvent);
     }
     // drop
-    case NS_DRAGDROP_DROP: {
+    case eDrop: {
       nsCOMPtr<nsIDOMDragEvent> dragEvent = do_QueryInterface(aEvent);
       return Drop(dragEvent);
     }
@@ -454,10 +454,10 @@ nsEditorEventListener::HandleEvent(nsIDOMEvent* aEvent)
       return MouseClick(mouseEvent);
     }
     // focus
-    case NS_FOCUS_CONTENT:
+    case eFocus:
       return Focus(aEvent);
     // blur
-    case NS_BLUR_CONTENT:
+    case eBlur:
       return Blur(aEvent);
     // text
     case NS_COMPOSITION_CHANGE:
diff --git a/editor/libeditor/nsHTMLEditorEventListener.cpp b/editor/libeditor/nsHTMLEditorEventListener.cpp
index 36025daebd..7e2aed530a 100644
--- a/editor/libeditor/nsHTMLEditorEventListener.cpp
+++ b/editor/libeditor/nsHTMLEditorEventListener.cpp
@@ -86,7 +86,7 @@ nsHTMLEditorEventListener::MouseDown(nsIDOMMouseEvent* aMouseEvent)
 
   // Detect only "context menu" click
   // XXX This should be easier to do!
-  // But eDOMEvents_contextmenu and NS_CONTEXTMENU is not exposed in any event
+  // But eDOMEvents_contextmenu and eContextMenu is not exposed in any event
   // interface :-(
   int16_t buttonNumber;
   nsresult rv = aMouseEvent->GetButton(&buttonNumber);
diff --git a/gfx/layers/apz/src/APZCTreeManager.cpp b/gfx/layers/apz/src/APZCTreeManager.cpp
index 425ec16e4e..7c421e3d48 100644
--- a/gfx/layers/apz/src/APZCTreeManager.cpp
+++ b/gfx/layers/apz/src/APZCTreeManager.cpp
@@ -914,8 +914,8 @@ APZCTreeManager::UpdateWheelTransaction(WidgetInputEvent& aEvent)
    case eMouseDown:
    case eMouseDoubleClick:
    case eMouseClick:
-   case NS_CONTEXTMENU:
-   case NS_DRAGDROP_DROP:
+   case eContextMenu:
+   case eDrop:
      txn->EndTransaction();
      return;
    default:
diff --git a/layout/base/nsDocumentViewer.cpp b/layout/base/nsDocumentViewer.cpp
index da6a1ff20a..21b60cbc4e 100644
--- a/layout/base/nsDocumentViewer.cpp
+++ b/layout/base/nsDocumentViewer.cpp
@@ -981,7 +981,7 @@ nsDocumentViewer::LoadComplete(nsresult aStatus)
   if(window &&
      (NS_SUCCEEDED(aStatus) || aStatus == NS_ERROR_PARSED_DATA_CACHED)) {
     nsEventStatus status = nsEventStatus_eIgnore;
-    WidgetEvent event(true, NS_LOAD);
+    WidgetEvent event(true, eLoad);
     event.mFlags.mBubbles = false;
     event.mFlags.mCancelable = false;
      // XXX Dispatching to |window|, but using |document| as the target.
@@ -1390,7 +1390,7 @@ nsDocumentViewer::PageHide(bool aIsUnload)
 
     // Now, fire an Unload event to the document...
     nsEventStatus status = nsEventStatus_eIgnore;
-    WidgetEvent event(true, NS_PAGE_UNLOAD);
+    WidgetEvent event(true, eUnload);
     event.mFlags.mBubbles = false;
     // XXX Dispatching to |window|, but using |document| as the target.
     event.target = mDocument;
diff --git a/layout/base/nsPresShell.cpp b/layout/base/nsPresShell.cpp
index 84dea61875..126b445895 100644
--- a/layout/base/nsPresShell.cpp
+++ b/layout/base/nsPresShell.cpp
@@ -6338,14 +6338,14 @@ PresShell::UpdateActivePointerState(WidgetGUIEvent* aEvent)
                               new PointerInfo(false, mouseEvent->inputSource, true));
     }
     break;
-  case NS_POINTER_DOWN:
+  case ePointerDown:
     // In this case we switch pointer to active state
     if (WidgetPointerEvent* pointerEvent = aEvent->AsPointerEvent()) {
       gActivePointersIds->Put(pointerEvent->pointerId,
                               new PointerInfo(true, pointerEvent->inputSource, pointerEvent->isPrimary));
     }
     break;
-  case NS_POINTER_UP:
+  case ePointerUp:
     // In this case we remove information about pointer or turn off active state
     if (WidgetPointerEvent* pointerEvent = aEvent->AsPointerEvent()) {
       if(pointerEvent->inputSource != nsIDOMMouseEvent::MOZ_SOURCE_TOUCH) {
@@ -6659,13 +6659,13 @@ DispatchPointerFromMouseOrTouch(PresShell* aShell,
       if (mouseEvent->buttons == 0) {
         button = -1;
       }
-      pointerMessage = NS_POINTER_MOVE;
+      pointerMessage = ePointerMove;
       break;
     case eMouseUp:
-      pointerMessage = NS_POINTER_UP;
+      pointerMessage = ePointerUp;
       break;
     case eMouseDown:
-      pointerMessage = NS_POINTER_DOWN;
+      pointerMessage = ePointerDown;
       break;
     default:
       return NS_OK;
@@ -6685,13 +6685,13 @@ DispatchPointerFromMouseOrTouch(PresShell* aShell,
     // copy the event
     switch (touchEvent->mMessage) {
     case NS_TOUCH_MOVE:
-      pointerMessage = NS_POINTER_MOVE;
+      pointerMessage = ePointerMove;
       break;
     case NS_TOUCH_END:
-      pointerMessage = NS_POINTER_UP;
+      pointerMessage = ePointerUp;
       break;
     case NS_TOUCH_START:
-      pointerMessage = NS_POINTER_DOWN;
+      pointerMessage = ePointerDown;
       break;
     case NS_TOUCH_CANCEL:
       pointerMessage = ePointerCancel;
@@ -7427,7 +7427,7 @@ PresShell::HandleEvent(nsIFrame* aFrame,
     }
 
     if (aEvent->mClass == ePointerEventClass &&
-        aEvent->mMessage != NS_POINTER_DOWN) {
+        aEvent->mMessage != ePointerDown) {
       if (WidgetPointerEvent* pointerEvent = aEvent->AsPointerEvent()) {
         uint32_t pointerId = pointerEvent->pointerId;
         nsIContent* pointerCapturingContent = GetPointerCapturingContent(pointerId);
@@ -7442,10 +7442,10 @@ PresShell::HandleEvent(nsIFrame* aFrame,
             frame = capturingFrame;
           }
 
-          if (pointerEvent->mMessage == NS_POINTER_UP ||
+          if (pointerEvent->mMessage == ePointerUp ||
               pointerEvent->mMessage == ePointerCancel) {
             // Implicitly releasing capture for given pointer.
-            // ePointerLostCapture should be send after NS_POINTER_UP or
+            // ePointerLostCapture should be send after ePointerUp or
             // ePointerCancel.
             releasePointerCaptureCaller.SetTarget(pointerId, pointerCapturingContent);
           }
@@ -7873,7 +7873,7 @@ PresShell::HandleEventInternal(WidgetEvent* aEvent, nsEventStatus* aStatus)
         isHandlingUserInput = true;
         break;
 
-      case NS_DRAGDROP_DROP: {
+      case eDrop: {
         nsCOMPtr<nsIDragSession> session = nsContentUtils::GetDragSession();
         if (session) {
           bool onlyChromeDrop = false;
@@ -7896,7 +7896,7 @@ PresShell::HandleEventInternal(WidgetEvent* aEvent, nsEventStatus* aStatus)
       }
     }
 
-    if (aEvent->mMessage == NS_CONTEXTMENU) {
+    if (aEvent->mMessage == eContextMenu) {
       WidgetMouseEvent* mouseEvent = aEvent->AsMouseEvent();
       if (mouseEvent->context == WidgetMouseEvent::eContextMenuKey &&
           !AdjustContextMenuKeyEvent(mouseEvent)) {
diff --git a/layout/xul/nsImageBoxFrame.cpp b/layout/xul/nsImageBoxFrame.cpp
index 2238584a36..814f666fdc 100644
--- a/layout/xul/nsImageBoxFrame.cpp
+++ b/layout/xul/nsImageBoxFrame.cpp
@@ -103,7 +103,7 @@ nsImageBoxFrameEvent::Run()
 void
 FireImageDOMEvent(nsIContent* aContent, EventMessage aMessage)
 {
-  NS_ASSERTION(aMessage == NS_LOAD || aMessage == NS_LOAD_ERROR,
+  NS_ASSERTION(aMessage == eLoad || aMessage == eLoadError,
                "invalid message");
 
   nsCOMPtr<nsIRunnable> event = new nsImageBoxFrameEvent(aContent, aMessage);
@@ -735,13 +735,13 @@ nsImageBoxFrame::OnLoadComplete(imgIRequest* aRequest, nsresult aStatus)
 {
   if (NS_SUCCEEDED(aStatus)) {
     // Fire an onload DOM event.
-    FireImageDOMEvent(mContent, NS_LOAD);
+    FireImageDOMEvent(mContent, eLoad);
   } else {
     // Fire an onerror DOM event.
     mIntrinsicSize.SizeTo(0, 0);
     PresContext()->PresShell()->
       FrameNeedsReflow(this, nsIPresShell::eStyleChange, NS_FRAME_IS_DIRTY);
-    FireImageDOMEvent(mContent, NS_LOAD_ERROR);
+    FireImageDOMEvent(mContent, eLoadError);
   }
 
   return NS_OK;
diff --git a/layout/xul/nsMenuFrame.cpp b/layout/xul/nsMenuFrame.cpp
index a0bf10540c..669288225e 100644
--- a/layout/xul/nsMenuFrame.cpp
+++ b/layout/xul/nsMenuFrame.cpp
@@ -434,7 +434,7 @@ nsMenuFrame::HandleEvent(nsPresContext* aPresContext,
            (aEvent->mMessage == eMouseUp &&
             aEvent->AsMouseEvent()->button == WidgetMouseEvent::eRightButton) &&
 #else
-           aEvent->mMessage == NS_CONTEXTMENU &&
+           aEvent->mMessage == eContextMenu &&
 #endif
            onmenu && !IsMenu() && !IsDisabled()) {
     // if this menu is a context menu it accepts right-clicks...fire away!
diff --git a/layout/xul/tree/nsTreeBodyFrame.cpp b/layout/xul/tree/nsTreeBodyFrame.cpp
index bdb1821d9c..58cd8d9861 100644
--- a/layout/xul/tree/nsTreeBodyFrame.cpp
+++ b/layout/xul/tree/nsTreeBodyFrame.cpp
@@ -2709,7 +2709,7 @@ nsTreeBodyFrame::HandleEvent(nsPresContext* aPresContext,
     // Indicate that the drop is allowed by preventing the default behaviour.
     if (mSlots->mDropAllowed)
       *aEventStatus = nsEventStatus_eConsumeNoDefault;
-  } else if (aEvent->mMessage == NS_DRAGDROP_DROP) {
+  } else if (aEvent->mMessage == eDrop) {
      // this event was meant for another frame, so ignore it
      if (!mSlots)
        return NS_OK;
diff --git a/testing/web-platform/mozilla/meta/service-workers/service-worker/__dir__.ini b/testing/web-platform/mozilla/meta/service-workers/service-worker/__dir__.ini
new file mode 100644
index 0000000000..57c38e8b32
--- /dev/null
+++ b/testing/web-platform/mozilla/meta/service-workers/service-worker/__dir__.ini
@@ -0,0 +1,3 @@
+prefs: [dom.serviceWorkers.enabled: true,
+        dom.serviceWorkers.interception.enabled: true,
+        dom.serviceWorkers.interception.opaque.enabled: true]
diff --git a/testing/web-platform/mozilla/meta/service-workers/service-worker/fetch-frame-resource.https.html.ini b/testing/web-platform/mozilla/meta/service-workers/service-worker/fetch-frame-resource.https.html.ini
deleted file mode 100644
index 1245221223..0000000000
--- a/testing/web-platform/mozilla/meta/service-workers/service-worker/fetch-frame-resource.https.html.ini
+++ /dev/null
@@ -1,10 +0,0 @@
-[fetch-frame-resource.https.html]
-  type: testharness
-  [CORS type response could be loaded in the iframe.]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1184967
-    expected: FAIL
-
-  [CORS type response could be loaded in the new window.]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1184967
-    expected: FAIL
-
diff --git a/testing/web-platform/mozilla/tests/service-workers/service-worker/fetch-frame-resource.https.html b/testing/web-platform/mozilla/tests/service-workers/service-worker/fetch-frame-resource.https.html
index fca530b4c5..156880faa1 100644
--- a/testing/web-platform/mozilla/tests/service-workers/service-worker/fetch-frame-resource.https.html
+++ b/testing/web-platform/mozilla/tests/service-workers/service-worker/fetch-frame-resource.https.html
@@ -14,6 +14,63 @@ if (window.testRunner) {
   testRunner.setCanOpenWindows();
 }
 
+function getLoadedObject(win, contentFunc, closeFunc) {
+  return new Promise(function(resolve) {
+      function done(contentString) {
+        var result = null;
+        // fetch-access-control.py returns a string like "report( <json> )".
+        // Eval the returned string with a report functionto get the json
+        // object.
+        try {
+          function report(obj) { result = obj };
+          eval(contentString);
+        } catch(e) {
+          // just resolve null if we get unexpected page content
+        }
+        closeFunc(win);
+        resolve(result);
+      }
+
+      // We can't catch the network error on window. So we use the timer.
+      var timeout = setTimeout(function() {
+          // Failure pages are considered cross-origin in some browsers.  This
+          // means you cannot even .resolve() the window because the check for
+          // the .then property will throw.  Instead, treat cross-origin
+          // failure pages as the empty string which will fail to parse as the
+          // expected json result.
+          var content = '';
+          try {
+            content = contentFunc(win);
+          } catch(e) {
+            // use default empty string for cross-domain window
+          }
+          done(content);
+        }, 5000);
+
+      win.onload = function() {
+          clearTimeout(timeout);
+          var content = contentFunc(win);
+          done(content);
+        };
+    });
+}
+
+function getLoadedFrameAsObject(frame) {
+  return getLoadedObject(frame, function(f) {
+      return f.contentDocument.body.textContent;
+    }, function(f) {
+      f.parentNode.removeChild(f);
+    });
+}
+
+function getLoadedWindowAsObject(win) {
+  return getLoadedObject(win, function(w) {
+      return w.document.body.textContent
+    }, function(w) {
+      w.close();
+    });
+}
+
 async_test(function(t) {
     var scope = 'resources/fetch-frame-resource/frame-basic';
     service_worker_unregister_and_register(t, worker, scope)
@@ -21,16 +78,18 @@ async_test(function(t) {
           return wait_for_state(t, reg.installing, 'activated');
         })
       .then(function() {
-          return with_iframe(
+          var frame = document.createElement('iframe');
+          frame.src =
             scope + '?url=' +
-            encodeURIComponent(host_info['HTTP_ORIGIN'] + path));
+            encodeURIComponent(host_info['HTTPS_ORIGIN'] + path);
+          document.body.appendChild(frame);
+          return getLoadedFrameAsObject(frame);
         })
-      .then(function(frame) {
-          assert_not_equals(
-            frame.contentDocument.body.textContent,
-            '',
+      .then(function(result) {
+          assert_equals(
+            result.jsonpResult,
+            'success',
             'Basic type response could be loaded in the iframe.');
-          frame.remove();
           return service_worker_unregister_and_done(t, scope);
         })
       .catch(unreached_rejection(t));
@@ -46,24 +105,20 @@ async_test(function(t) {
           var frame = document.createElement('iframe');
           frame.src =
             scope + '?mode=cors&url=' +
-            encodeURIComponent(host_info['HTTP_REMOTE_ORIGIN'] + path +
-                               '?ACAOrigin=' + host_info['HTTP_ORIGIN']);
+            encodeURIComponent(host_info['HTTPS_REMOTE_ORIGIN'] + path +
+                               '?ACAOrigin=' + host_info['HTTPS_ORIGIN']);
           document.body.appendChild(frame);
-          // We can't catch the network error on iframe. So we use the timer.
-          return new Promise(function(resolve) {
-              setTimeout(function() { resolve(frame); }, 1000);
-            });
+          return getLoadedFrameAsObject(frame);
         })
-      .then(function(frame) {
+      .then(function(result) {
           assert_equals(
-            frame.contentDocument.body.textContent,
-            '',
-            'CORS type response could not be loaded in the iframe.');
-          frame.remove();
+            result.jsonpResult,
+            'success',
+            'CORS type response could be loaded in the iframe.');
           return service_worker_unregister_and_done(t, scope);
         })
       .catch(unreached_rejection(t));
-  }, 'CORS type response could not be loaded in the iframe.');
+  }, 'CORS type response could be loaded in the iframe.');
 
 async_test(function(t) {
     var scope = 'resources/fetch-frame-resource/frame-opaque';
@@ -75,19 +130,15 @@ async_test(function(t) {
           var frame = document.createElement('iframe');
           frame.src =
             scope + '?mode=no-cors&url=' +
-            encodeURIComponent(host_info['HTTP_REMOTE_ORIGIN'] + path);
+            encodeURIComponent(host_info['HTTPS_REMOTE_ORIGIN'] + path);
           document.body.appendChild(frame);
-          // We can't catch the network error on iframe. So we use the timer.
-          return new Promise(function(resolve) {
-              setTimeout(function() { resolve(frame); }, 1000);
-            });
+          return getLoadedFrameAsObject(frame);
         })
-      .then(function(frame) {
+      .then(function(result) {
           assert_equals(
-            frame.contentDocument.body.textContent,
-            '',
+            result,
+            null,
             'Opaque type response could not be loaded in the iframe.');
-          frame.remove();
           return service_worker_unregister_and_done(t, scope);
         })
       .catch(unreached_rejection(t));
@@ -100,19 +151,16 @@ async_test(function(t) {
           return wait_for_state(t, reg.installing, 'activated');
         })
       .then(function() {
-          return new Promise(function(resolve) {
-              var win = window.open(
-                scope + '?url=' +
-                encodeURIComponent(host_info['HTTP_ORIGIN'] + path));
-              win.onload = function() { resolve(win); };
-            });
+          var win = window.open(
+            scope + '?url=' +
+            encodeURIComponent(host_info['HTTPS_ORIGIN'] + path));
+          return getLoadedWindowAsObject(win);
         })
-      .then(function(win) {
-          assert_not_equals(
-            win.document.body.textContent,
-            '',
+      .then(function(result) {
+          assert_equals(
+            result.jsonpResult,
+            'success',
             'Basic type response could be loaded in the new window.');
-          win.close();
           return service_worker_unregister_and_done(t, scope);
         })
       .catch(unreached_rejection(t));
@@ -127,23 +175,19 @@ async_test(function(t) {
       .then(function() {
           var win = window.open(
             scope + '?mode=cors&url=' +
-            encodeURIComponent(host_info['HTTP_REMOTE_ORIGIN'] + path +
-                               '?ACAOrigin=' + host_info['HTTP_ORIGIN']));
-          // We can't catch the network error on window. So we use the timer.
-          return new Promise(function(resolve) {
-              setTimeout(function() { resolve(win); }, 1000);
-            });
+            encodeURIComponent(host_info['HTTPS_REMOTE_ORIGIN'] + path +
+                               '?ACAOrigin=' + host_info['HTTPS_ORIGIN']));
+          return getLoadedWindowAsObject(win);
         })
-      .then(function(win) {
+      .then(function(result) {
           assert_equals(
-            win.document.body.textContent,
-            '',
-            'CORS type response could not be loaded in the new window.');
-          win.close();
+            result.jsonpResult,
+            'success',
+            'CORS type response could be loaded in the new window.');
           return service_worker_unregister_and_done(t, scope);
         })
       .catch(unreached_rejection(t));
-  }, 'CORS type response could not be loaded in the new window.');
+  }, 'CORS type response could be loaded in the new window.');
 
 async_test(function(t) {
     var scope = 'resources/fetch-frame-resource/window-opaque';
@@ -154,18 +198,14 @@ async_test(function(t) {
       .then(function() {
           var win = window.open(
             scope + '?mode=no-cors&url=' +
-            encodeURIComponent(host_info['HTTP_REMOTE_ORIGIN'] + path));
-          // We can't catch the network error on window. So we use the timer.
-          return new Promise(function(resolve) {
-              setTimeout(function() { resolve(win); }, 1000);
-            });
+            encodeURIComponent(host_info['HTTPS_REMOTE_ORIGIN'] + path));
+          return getLoadedWindowAsObject(win);
         })
-      .then(function(win) {
+      .then(function(result) {
           assert_equals(
-            win.document.body.textContent,
-            '',
+            result,
+            null,
             'Opaque type response could not be loaded in the new window.');
-          win.close();
           return service_worker_unregister_and_done(t, scope);
         })
       .catch(unreached_rejection(t));
diff --git a/widget/EventMessageList.h b/widget/EventMessageList.h
index 7a19ddeb68..7bedc86fbf 100644
--- a/widget/EventMessageList.h
+++ b/widget/EventMessageList.h
@@ -64,55 +64,55 @@ NS_EVENT_MESSAGE(eMouseLongTap,         eMouseEventFirst + 36)
 
 // Pointer spec events
 NS_EVENT_MESSAGE(ePointerEventFirst,    4400)
-NS_EVENT_MESSAGE(NS_POINTER_MOVE,         ePointerEventFirst)
-NS_EVENT_MESSAGE(NS_POINTER_UP,           ePointerEventFirst + 1)
-NS_EVENT_MESSAGE(NS_POINTER_DOWN,         ePointerEventFirst + 2)
-NS_EVENT_MESSAGE(NS_POINTER_OVER,         ePointerEventFirst + 22)
-NS_EVENT_MESSAGE(NS_POINTER_OUT,          ePointerEventFirst + 23)
-NS_EVENT_MESSAGE(NS_POINTER_ENTER,        ePointerEventFirst + 24)
+NS_EVENT_MESSAGE(ePointerMove,          ePointerEventFirst)
+NS_EVENT_MESSAGE(ePointerUp,            ePointerEventFirst + 1)
+NS_EVENT_MESSAGE(ePointerDown,          ePointerEventFirst + 2)
+NS_EVENT_MESSAGE(ePointerOver,          ePointerEventFirst + 22)
+NS_EVENT_MESSAGE(ePointerOut,           ePointerEventFirst + 23)
+NS_EVENT_MESSAGE(ePointerEnter,         ePointerEventFirst + 24)
 NS_EVENT_MESSAGE(ePointerLeave,         ePointerEventFirst + 25)
 NS_EVENT_MESSAGE(ePointerCancel,        ePointerEventFirst + 26)
 NS_EVENT_MESSAGE(ePointerGotCapture,    ePointerEventFirst + 27)
 NS_EVENT_MESSAGE(ePointerLostCapture,   ePointerEventFirst + 28)
 NS_EVENT_MESSAGE(ePointerEventLast,     ePointerLostCapture)
 
-NS_EVENT_MESSAGE(NS_CONTEXTMENU_MESSAGE_START, 500)
-NS_EVENT_MESSAGE(NS_CONTEXTMENU,        NS_CONTEXTMENU_MESSAGE_START)
+NS_EVENT_MESSAGE(eContextMenuFirst,     500)
+NS_EVENT_MESSAGE(eContextMenu,          eContextMenuFirst)
 
-NS_EVENT_MESSAGE(NS_STREAM_EVENT_START, 1100)
-NS_EVENT_MESSAGE(NS_LOAD,               NS_STREAM_EVENT_START)
-NS_EVENT_MESSAGE(NS_PAGE_UNLOAD,        NS_STREAM_EVENT_START + 1)
-NS_EVENT_MESSAGE(NS_HASHCHANGE,         NS_STREAM_EVENT_START + 2)
-NS_EVENT_MESSAGE(NS_IMAGE_ABORT,        NS_STREAM_EVENT_START + 3)
-NS_EVENT_MESSAGE(NS_LOAD_ERROR,         NS_STREAM_EVENT_START + 4)
-NS_EVENT_MESSAGE(NS_POPSTATE,           NS_STREAM_EVENT_START + 5)
-NS_EVENT_MESSAGE(NS_BEFORE_PAGE_UNLOAD, NS_STREAM_EVENT_START + 6)
-NS_EVENT_MESSAGE(NS_PAGE_RESTORE,       NS_STREAM_EVENT_START + 7)
-NS_EVENT_MESSAGE(NS_READYSTATECHANGE,   NS_STREAM_EVENT_START + 8)
+NS_EVENT_MESSAGE(eStreamEventFirst,     1100)
+NS_EVENT_MESSAGE(eLoad,                 eStreamEventFirst)
+NS_EVENT_MESSAGE(eUnload,               eStreamEventFirst + 1)
+NS_EVENT_MESSAGE(eHashChange,           eStreamEventFirst + 2)
+NS_EVENT_MESSAGE(eImageAbort,           eStreamEventFirst + 3)
+NS_EVENT_MESSAGE(eLoadError,            eStreamEventFirst + 4)
+NS_EVENT_MESSAGE(ePopState,             eStreamEventFirst + 5)
+NS_EVENT_MESSAGE(eBeforeUnload,         eStreamEventFirst + 6)
+NS_EVENT_MESSAGE(eReadyStateChange,     eStreamEventFirst + 8)
  
-NS_EVENT_MESSAGE(NS_FORM_EVENT_START,   1200)
-NS_EVENT_MESSAGE(NS_FORM_SUBMIT,        NS_FORM_EVENT_START)
-NS_EVENT_MESSAGE(NS_FORM_RESET,         NS_FORM_EVENT_START + 1)
-NS_EVENT_MESSAGE(NS_FORM_CHANGE,        NS_FORM_EVENT_START + 2)
-NS_EVENT_MESSAGE(NS_FORM_SELECTED,      NS_FORM_EVENT_START + 3)
-NS_EVENT_MESSAGE(NS_FORM_INVALID,       NS_FORM_EVENT_START + 4)
+NS_EVENT_MESSAGE(eFormEventFirst,       1200)
+NS_EVENT_MESSAGE(eFormSubmit,           eFormEventFirst)
+NS_EVENT_MESSAGE(eFormReset,            eFormEventFirst + 1)
+NS_EVENT_MESSAGE(eFormChange,           eFormEventFirst + 2)
+NS_EVENT_MESSAGE(eFormSelect,           eFormEventFirst + 3)
+NS_EVENT_MESSAGE(eFormInvalid,          eFormEventFirst + 4)
 
 //Need separate focus/blur notifications for non-native widgets
-NS_EVENT_MESSAGE(NS_FOCUS_EVENT_START,  1300)
-NS_EVENT_MESSAGE(NS_FOCUS_CONTENT,      NS_FOCUS_EVENT_START)
-NS_EVENT_MESSAGE(NS_BLUR_CONTENT,       NS_FOCUS_EVENT_START + 1)
+NS_EVENT_MESSAGE(eFocusEventFirst,      1300)
+NS_EVENT_MESSAGE(eFocus,                eFocusEventFirst)
+NS_EVENT_MESSAGE(eBlur,                 eFocusEventFirst + 1)
 
-NS_EVENT_MESSAGE(NS_DRAGDROP_EVENT_START, 1400)
-NS_EVENT_MESSAGE(NS_DRAGDROP_ENTER,     NS_DRAGDROP_EVENT_START)
-NS_EVENT_MESSAGE(NS_DRAGDROP_OVER,      NS_DRAGDROP_EVENT_START + 1)
-NS_EVENT_MESSAGE(NS_DRAGDROP_EXIT,      NS_DRAGDROP_EVENT_START + 2)
-NS_EVENT_MESSAGE(NS_DRAGDROP_DRAGDROP,  NS_DRAGDROP_EVENT_START + 3)
-NS_EVENT_MESSAGE(NS_DRAGDROP_GESTURE,   NS_DRAGDROP_EVENT_START + 4)
-NS_EVENT_MESSAGE(NS_DRAGDROP_DRAG,      NS_DRAGDROP_EVENT_START + 5)
-NS_EVENT_MESSAGE(NS_DRAGDROP_END,       NS_DRAGDROP_EVENT_START + 6)
-NS_EVENT_MESSAGE(NS_DRAGDROP_START,     NS_DRAGDROP_EVENT_START + 7)
-NS_EVENT_MESSAGE(NS_DRAGDROP_DROP,      NS_DRAGDROP_EVENT_START + 8)
-NS_EVENT_MESSAGE(NS_DRAGDROP_LEAVE,     NS_DRAGDROP_EVENT_START + 9)
+NS_EVENT_MESSAGE(eDragDropEventFirst,   1400)
+NS_EVENT_MESSAGE(NS_DRAGDROP_ENTER,     eDragDropEventFirst)
+NS_EVENT_MESSAGE(NS_DRAGDROP_OVER,      eDragDropEventFirst + 1)
+NS_EVENT_MESSAGE(NS_DRAGDROP_EXIT,      eDragDropEventFirst + 2)
+NS_EVENT_MESSAGE(NS_DRAGDROP_DRAGDROP,  eDragDropEventFirst + 3)
+NS_EVENT_MESSAGE(NS_DRAGDROP_GESTURE,   eDragDropEventFirst + 4)
+NS_EVENT_MESSAGE(NS_DRAGDROP_DRAG,      eDragDropEventFirst + 5)
+NS_EVENT_MESSAGE(NS_DRAGDROP_END,       eDragDropEventFirst + 6)
+NS_EVENT_MESSAGE(eDragStart,            eDragDropEventFirst + 7)
+NS_EVENT_MESSAGE(eDrop,                 eDragDropEventFirst + 8)
+NS_EVENT_MESSAGE(eDragLeave,            eDragDropEventFirst + 9)
+NS_EVENT_MESSAGE(eDragDropEventLast,    eDragLeave)
 
 // Events for popups
 NS_EVENT_MESSAGE(NS_XUL_EVENT_START,    1500)
@@ -176,12 +176,15 @@ NS_EVENT_MESSAGE(NS_COMPOSITION_COMMIT_AS_IS, NS_COMPOSITION_EVENT_START + 4)
 // Its mRanges should be nullptr.
 NS_EVENT_MESSAGE(NS_COMPOSITION_COMMIT,       NS_COMPOSITION_EVENT_START + 5)
 
-// UI events
-NS_EVENT_MESSAGE(NS_UI_EVENT_START,     2500)
-// this is not to be confused with NS_ACTIVATE!
-NS_EVENT_MESSAGE(NS_UI_ACTIVATE,        NS_UI_EVENT_START)
-NS_EVENT_MESSAGE(NS_UI_FOCUSIN,         NS_UI_EVENT_START + 1)
-NS_EVENT_MESSAGE(NS_UI_FOCUSOUT,        NS_UI_EVENT_START + 2)
+// Following events are defined for deprecated DOM events which are using
+// InternalUIEvent class.
+NS_EVENT_MESSAGE(eLegacyUIEventFirst,   2500)
+// DOMActivate (mapped with the DOM event and used internally)
+NS_EVENT_MESSAGE(eLegacyDOMActivate,    eLegacyUIEventFirst)
+// DOMFocusIn (only mapped with the DOM event)
+NS_EVENT_MESSAGE(eLegacyDOMFocusIn,     eLegacyUIEventFirst + 1)
+// DOMFocusOut (only mapped with the DOM event)
+NS_EVENT_MESSAGE(eLegacyDOMFocusOut,    eLegacyUIEventFirst + 2)
 
 // pagetransition events
 NS_EVENT_MESSAGE(NS_PAGETRANSITION_START, 2700)
diff --git a/widget/MouseEvents.h b/widget/MouseEvents.h
index 0186f1c6ea..dd9cdea54b 100644
--- a/widget/MouseEvents.h
+++ b/widget/MouseEvents.h
@@ -229,7 +229,7 @@ public:
         mFlags.mBubbles = false;
         mFlags.mCancelable = false;
         break;
-      case NS_CONTEXTMENU:
+      case eContextMenu:
         button = (context == eNormal) ? eRightButton : eLeftButton;
         break;
       default:
@@ -240,10 +240,10 @@ public:
 #ifdef DEBUG
   virtual ~WidgetMouseEvent()
   {
-    NS_WARN_IF_FALSE(mMessage != NS_CONTEXTMENU ||
+    NS_WARN_IF_FALSE(mMessage != eContextMenu ||
                      button ==
                        ((context == eNormal) ? eRightButton : eLeftButton),
-                     "Wrong button set to NS_CONTEXTMENU event?");
+                     "Wrong button set to eContextMenu event?");
   }
 #endif
 
@@ -287,7 +287,7 @@ public:
    */
   bool IsContextMenuKeyEvent() const
   {
-    return mMessage == NS_CONTEXTMENU && context == eContextMenuKey;
+    return mMessage == eContextMenu && context == eContextMenuKey;
   }
 
   /**
@@ -323,7 +323,7 @@ public:
   {
     mFlags.mCancelable =
       (aMessage != NS_DRAGDROP_EXIT &&
-       aMessage != NS_DRAGDROP_LEAVE &&
+       aMessage != eDragLeave &&
        aMessage != NS_DRAGDROP_END);
   }
 
@@ -625,7 +625,7 @@ public:
   void UpdateFlags()
   {
     switch (mMessage) {
-      case NS_POINTER_ENTER:
+      case ePointerEnter:
       case ePointerLeave:
         mFlags.mBubbles = false;
         mFlags.mCancelable = false;
diff --git a/widget/WidgetEventImpl.cpp b/widget/WidgetEventImpl.cpp
index ed9a958b9f..148b91d2c9 100644
--- a/widget/WidgetEventImpl.cpp
+++ b/widget/WidgetEventImpl.cpp
@@ -106,9 +106,9 @@ WidgetEvent::HasDragEventMessage() const
     case NS_DRAGDROP_GESTURE:
     case NS_DRAGDROP_DRAG:
     case NS_DRAGDROP_END:
-    case NS_DRAGDROP_START:
-    case NS_DRAGDROP_DROP:
-    case NS_DRAGDROP_LEAVE:
+    case eDragStart:
+    case eDrop:
+    case eDragLeave:
       return true;
     default:
       return false;
diff --git a/widget/cocoa/nsChildView.mm b/widget/cocoa/nsChildView.mm
index dc04e0c8bb..c86118973f 100644
--- a/widget/cocoa/nsChildView.mm
+++ b/widget/cocoa/nsChildView.mm
@@ -5081,7 +5081,7 @@ PanGestureTypeForEvent(NSEvent* aEvent)
       return nil;
   }
 
-  WidgetMouseEvent geckoEvent(true, NS_CONTEXTMENU, mGeckoChild,
+  WidgetMouseEvent geckoEvent(true, eContextMenu, mGeckoChild,
                               WidgetMouseEvent::eReal);
   [self convertCocoaMouseEvent:theEvent toGeckoEvent:&geckoEvent];
   geckoEvent.button = WidgetMouseEvent::eRightButton;
@@ -5726,8 +5726,7 @@ PanGestureTypeForEvent(NSEvent* aEvent)
       // cancelled or not as there isn't actually a means to stop the drag
       mDragService->FireDragEventAtSource(NS_DRAGDROP_DRAG);
       dragSession->SetCanDrop(false);
-    }
-    else if (aMessage == NS_DRAGDROP_DROP) {
+    } else if (aMessage == eDrop) {
       // We make the assumption that the dragOver handlers have correctly set
       // the |canDrop| property of the Drag Session.
       bool canDrop = false;
@@ -5792,7 +5791,7 @@ PanGestureTypeForEvent(NSEvent* aEvent)
         return [self dragOperationFromDragAction:dragAction];
       }
       case NS_DRAGDROP_EXIT:
-      case NS_DRAGDROP_DROP: {
+      case eDrop: {
         nsCOMPtr<nsIDOMNode> sourceNode;
         dragSession->GetSourceNode(getter_AddRefs(sourceNode));
         if (!sourceNode) {
@@ -5852,7 +5851,7 @@ PanGestureTypeForEvent(NSEvent* aEvent)
 - (BOOL)performDragOperation:(id <NSDraggingInfo>)sender
 {
   nsAutoRetainCocoaObject kungFuDeathGrip(self);
-  BOOL handled = [self doDragAction:NS_DRAGDROP_DROP sender:sender] != NSDragOperationNone;
+  BOOL handled = [self doDragAction:eDrop sender:sender] != NSDragOperationNone;
   NS_IF_RELEASE(mDragService);
   return handled;
 }
diff --git a/widget/gtk/nsDragService.cpp b/widget/gtk/nsDragService.cpp
index b874037ece..b6d09f0166 100644
--- a/widget/gtk/nsDragService.cpp
+++ b/widget/gtk/nsDragService.cpp
@@ -2007,7 +2007,7 @@ nsDragService::DispatchDropEvent()
     if (mTargetWindow->IsDestroyed())
         return FALSE;
 
-    EventMessage msg = mCanDrop ? NS_DRAGDROP_DROP : NS_DRAGDROP_EXIT;
+    EventMessage msg = mCanDrop ? eDrop : NS_DRAGDROP_EXIT;
 
     mTargetWindow->DispatchDragEvent(msg, mTargetWindowPoint, mTargetTime);
 
diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
index 0e0478ba14..2fe666523b 100644
--- a/widget/gtk/nsWindow.cpp
+++ b/widget/gtk/nsWindow.cpp
@@ -2693,7 +2693,7 @@ nsWindow::OnButtonPressEvent(GdkEventButton *aEvent)
     // right menu click on linux should also pop up a context menu
     if (domButton == WidgetMouseEvent::eRightButton &&
         MOZ_LIKELY(!mIsDestroyed)) {
-        WidgetMouseEvent contextMenuEvent(true, NS_CONTEXTMENU, this,
+        WidgetMouseEvent contextMenuEvent(true, eContextMenu, this,
                                           WidgetMouseEvent::eReal);
         InitButtonEvent(contextMenuEvent, aEvent);
         contextMenuEvent.pressure = mLastMotionPressure;
@@ -2958,7 +2958,7 @@ nsWindow::OnKeyPressEvent(GdkEventKey *aEvent)
     // before we dispatch a key, check if it's the context menu key.
     // If so, send a context menu key event instead.
     if (is_context_menu_key(event)) {
-        WidgetMouseEvent contextMenuEvent(true, NS_CONTEXTMENU, this,
+        WidgetMouseEvent contextMenuEvent(true, eContextMenu, this,
                                           WidgetMouseEvent::eReal,
                                           WidgetMouseEvent::eContextMenuKey);
 
diff --git a/widget/nsBaseWidget.cpp b/widget/nsBaseWidget.cpp
index eb7bdc4975..6def3c9fc1 100644
--- a/widget/nsBaseWidget.cpp
+++ b/widget/nsBaseWidget.cpp
@@ -2601,20 +2601,20 @@ case _value: eventName.AssignLiteral(_name) ; break
 
   switch(aGuiEvent->mMessage)
   {
-    _ASSIGN_eventName(NS_BLUR_CONTENT,"NS_BLUR_CONTENT");
+    _ASSIGN_eventName(eBlur,"eBlur");
     _ASSIGN_eventName(NS_DRAGDROP_GESTURE,"NS_DND_GESTURE");
-    _ASSIGN_eventName(NS_DRAGDROP_DROP,"NS_DND_DROP");
+    _ASSIGN_eventName(eDrop,"eDrop");
     _ASSIGN_eventName(NS_DRAGDROP_ENTER,"NS_DND_ENTER");
     _ASSIGN_eventName(NS_DRAGDROP_EXIT,"NS_DND_EXIT");
     _ASSIGN_eventName(NS_DRAGDROP_OVER,"NS_DND_OVER");
     _ASSIGN_eventName(NS_EDITOR_INPUT,"NS_EDITOR_INPUT");
-    _ASSIGN_eventName(NS_FOCUS_CONTENT,"NS_FOCUS_CONTENT");
-    _ASSIGN_eventName(NS_FORM_SELECTED,"NS_FORM_SELECTED");
-    _ASSIGN_eventName(NS_FORM_CHANGE,"NS_FORM_CHANGE");
-    _ASSIGN_eventName(NS_FORM_RESET,"NS_FORM_RESET");
-    _ASSIGN_eventName(NS_FORM_SUBMIT,"NS_FORM_SUBMIT");
-    _ASSIGN_eventName(NS_IMAGE_ABORT,"NS_IMAGE_ABORT");
-    _ASSIGN_eventName(NS_LOAD_ERROR,"NS_LOAD_ERROR");
+    _ASSIGN_eventName(eFocus,"eFocus");
+    _ASSIGN_eventName(eFormSelect,"eFormSelect");
+    _ASSIGN_eventName(eFormChange,"eFormChange");
+    _ASSIGN_eventName(eFormReset,"eFormReset");
+    _ASSIGN_eventName(eFormSubmit,"eFormSubmit");
+    _ASSIGN_eventName(eImageAbort,"eImageAbort");
+    _ASSIGN_eventName(eLoadError,"eLoadError");
     _ASSIGN_eventName(eKeyDown,"eKeyDown");
     _ASSIGN_eventName(eKeyPress,"eKeyPress");
     _ASSIGN_eventName(eKeyUp,"eKeyUp");
@@ -2625,13 +2625,13 @@ case _value: eventName.AssignLiteral(_name) ; break
     _ASSIGN_eventName(eMouseClick,"eMouseClick");
     _ASSIGN_eventName(eMouseDoubleClick,"eMouseDoubleClick");
     _ASSIGN_eventName(eMouseMove,"eMouseMove");
-    _ASSIGN_eventName(NS_LOAD,"NS_LOAD");
-    _ASSIGN_eventName(NS_POPSTATE,"NS_POPSTATE");
+    _ASSIGN_eventName(eLoad,"eLoad");
+    _ASSIGN_eventName(ePopState,"ePopState");
     _ASSIGN_eventName(NS_BEFORE_SCRIPT_EXECUTE,"NS_BEFORE_SCRIPT_EXECUTE");
     _ASSIGN_eventName(NS_AFTER_SCRIPT_EXECUTE,"NS_AFTER_SCRIPT_EXECUTE");
-    _ASSIGN_eventName(NS_PAGE_UNLOAD,"NS_PAGE_UNLOAD");
-    _ASSIGN_eventName(NS_HASHCHANGE,"NS_HASHCHANGE");
-    _ASSIGN_eventName(NS_READYSTATECHANGE,"NS_READYSTATECHANGE");
+    _ASSIGN_eventName(eUnload,"eUnload");
+    _ASSIGN_eventName(eHashChange,"eHashChange");
+    _ASSIGN_eventName(eReadyStateChange,"eReadyStateChange");
     _ASSIGN_eventName(NS_XUL_BROADCAST, "NS_XUL_BROADCAST");
     _ASSIGN_eventName(NS_XUL_COMMAND_UPDATE, "NS_XUL_COMMAND_UPDATE");
 
diff --git a/widget/qt/nsWindow.cpp b/widget/qt/nsWindow.cpp
index d384797a2f..538aa8dde8 100644
--- a/widget/qt/nsWindow.cpp
+++ b/widget/qt/nsWindow.cpp
@@ -1006,7 +1006,7 @@ nsWindow::mousePressEvent(QMouseEvent* aEvent)
     // Right click on linux should also pop up a context menu.
     if (event.button == WidgetMouseEvent::eRightButton &&
         MOZ_LIKELY(!mIsDestroyed)) {
-        WidgetMouseEvent contextMenuEvent(true, NS_CONTEXTMENU, this,
+        WidgetMouseEvent contextMenuEvent(true, eContextMenu, this,
                                           WidgetMouseEvent::eReal);
         InitMouseEvent(contextMenuEvent, aEvent, 1);
         DispatchEvent(&contextMenuEvent, status);
@@ -1140,7 +1140,7 @@ nsWindow::keyPressEvent(QKeyEvent* aEvent)
     // Before we dispatch a key, check if it's the context menu key.
     // If so, send a context menu key event instead.
     if (IsContextMenuKeyEvent(aEvent)) {
-        WidgetMouseEvent contextMenuEvent(true, NS_CONTEXTMENU, this,
+        WidgetMouseEvent contextMenuEvent(true, eContextMenu, this,
                                           WidgetMouseEvent::eReal,
                                           WidgetMouseEvent::eContextMenuKey);
         return DispatchEvent(&contextMenuEvent);
diff --git a/widget/windows/nsNativeDragTarget.cpp b/widget/windows/nsNativeDragTarget.cpp
index ffab0c402b..3592e56815 100644
--- a/widget/windows/nsNativeDragTarget.cpp
+++ b/widget/windows/nsNativeDragTarget.cpp
@@ -229,7 +229,7 @@ nsNativeDragTarget::ProcessDrag(EventMessage aEventMessage,
     *pdwEffect = DROPEFFECT_NONE;
   }
 
-  if (aEventMessage != NS_DRAGDROP_DROP) {
+  if (aEventMessage != eDrop) {
     // Get the cached drag effect from the drag service, the data member should
     // have been set by whoever handled the WidgetGUIEvent or nsIDOMEvent on
     // drags.
@@ -439,7 +439,7 @@ nsNativeDragTarget::Drop(LPDATAOBJECT pData,
   nsCOMPtr<nsIDragService> serv = mDragService;
 
   // Now process the native drag state and then dispatch the event
-  ProcessDrag(NS_DRAGDROP_DROP, grfKeyState, aPT, pdwEffect);
+  ProcessDrag(eDrop, grfKeyState, aPT, pdwEffect);
 
   nsCOMPtr<nsIDragSession> currentDragSession;
   serv->GetCurrentSession(getter_AddRefs(currentDragSession));
diff --git a/widget/windows/nsWindow.cpp b/widget/windows/nsWindow.cpp
index 1e079cbf21..02cdc900d5 100644
--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -3839,7 +3839,7 @@ nsWindow::DispatchMouseEvent(EventMessage aEventMessage, WPARAM wParam,
   WidgetMouseEvent event(true, aEventMessage, this, WidgetMouseEvent::eReal,
                          aIsContextMenuKey ? WidgetMouseEvent::eContextMenuKey :
                                              WidgetMouseEvent::eNormal);
-  if (aEventMessage == NS_CONTEXTMENU && aIsContextMenuKey) {
+  if (aEventMessage == eContextMenu && aIsContextMenuKey) {
     nsIntPoint zero(0, 0);
     InitEvent(event, &zero);
   } else {
@@ -4990,7 +4990,7 @@ nsWindow::ProcessMessage(UINT msg, WPARAM& wParam, LPARAM& lParam,
         pos = lParamToClient(lParam);
       }
 
-      result = DispatchMouseEvent(NS_CONTEXTMENU, wParam, pos, contextMenukey,
+      result = DispatchMouseEvent(eContextMenu, wParam, pos, contextMenukey,
                                   contextMenukey ?
                                     WidgetMouseEvent::eLeftButton :
                                     WidgetMouseEvent::eRightButton,
diff --git a/xpcom/base/nsMemoryReporterManager.cpp b/xpcom/base/nsMemoryReporterManager.cpp
index b79b364d06..618634001d 100644
--- a/xpcom/base/nsMemoryReporterManager.cpp
+++ b/xpcom/base/nsMemoryReporterManager.cpp
@@ -175,6 +175,7 @@ public:
 };
 NS_IMPL_ISUPPORTS(ResidentUniqueReporter, nsIMemoryReporter)
 
+#ifdef HAVE_MALLINFO
 #define HAVE_SYSTEM_HEAP_REPORTER 1
 nsresult
 SystemHeapSize(int64_t* aSizeOut)
@@ -194,6 +195,7 @@ SystemHeapSize(int64_t* aSizeOut)
     *aSizeOut = size_t(info.hblkhd) + size_t(info.uordblks);
     return NS_OK;
 }
+#endif
 
 #elif defined(__DragonFly__) || defined(__FreeBSD__) \
     || defined(__NetBSD__) || defined(__OpenBSD__) \