import changes from `dev' branch of rmottola/Arctic-Fox:

- Bug 1048131 - Remove MOZ_CAPTIVEDETECT and enable captive portal detector for all products. r=mcmanus (d2b2980c1)
- Bug 1048131 - Implement CaptivePortalService using nsICaptivePortalDetector r=mcmanus (d62c390d4)
- Bug 1048131 - Make some network events trigger a captive portal recheck r=mcmanus (8c19273f0)
- Bug 1166910 - Gecko changes for adding referrer attribute. r=hsivonen (46676ae77)
- Bug 1166910 - Referrer attribute for img tag. r=ckerschb, r=hsivonen, r=bz (f833f3e6c)
- Bug 1174913 - anchor and area referrer attributes. r=ckerschb, r=bz (f99a956be) (backend parts only)
- missing bits of Bug 1210302 - Part 1: Rename nsINetUtil.parseContentType() to parseResponseContentType(); r=mcmanus (eb8fba336)
- Bug 1210302 - Part 2: Rename NS_ParseContentType to NS_ParseResponseContentType; r=mcmanus,sicking (74f4cd98d)
- remaining bits of Bug 1210302 - Part 3: Add a NS_ParseRequestContentType API; r=mcmanus,sicking (56477b434)
- pointer style (ca5142301)
- Bug 1172109 - Name some anonymous structs to help out the analysis, r=terrence (775d17318)
- Bug 1173042 - Remove unused GCChunkSet and chunk hashing functions; r=ehoogeveen (357e0887d)
- Bug 1177778 - Allow HeapPtr destruction while shutting down the GC r=terrence (793654cb2)
- Bug 1181306 - Skip compacting phase when finishing an incremental GC non-incrementally r=terrence (7547c11ad)
- Bug 1162961 - Fix logspam in mochitest-dt by passing the URL along in network progress events;r=past (3b4c9048f)
- Bug 1149235 part 1. Move nsScriptLoadRequest into nsScriptLoader.h. r=sicking (df56a3e9d)
- Bug 1149235 part 2. Switch to using linked lists for nsScriptLoadRequest. r=sicking (7a0536b53)
- Bug 1149235 part 3. Store async requests in the scriptloader in two lists, so we don't have to grovel about looking for loaded ones. r=sicking (db45689c6)
- Bug 1154598. Keep better track of our script requests. r=smaug (a2232a237)
- Bug 1157995 - Tell the cycle collector about Navigator::mMediaDevices. r=smaug (9a9147bdf)
- Bug 1181619. Make sure we've entered a microtask before we call nsJSUtils::EvaluateString, and put those microtasks outside the relevant AutoEntryScripts so we report any possible exceptions before doing the microtask checkpoint. r=bholley (851e371ac)

dom/base/nsImageLoadingContent.cpp

@@ -48,6 +48,7 @@
 #include "mozilla/EventStates.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/ScriptSettings.h"
+#include "mozilla/Preferences.h"
 
 #ifdef LoadImage
 // Undefine LoadImage to prevent naming conflict with Windows.
@@ -940,14 +941,26 @@ nsImageLoadingContent::LoadImage(nsIURI* aNewURI,
     loadFlags |= imgILoader::LOAD_CORS_USE_CREDENTIALS;
   }
 
+  // get document wide referrer policy
+  mozilla::net::ReferrerPolicy referrerPolicy = aDocument->GetReferrerPolicy();
+  bool referrerAttributeEnabled = Preferences::GetBool("network.http.enablePerElementReferrer", false);
+  // if referrer attributes are enabled in preferences, load img referrer attribute
+  nsresult rv;
+  if (referrerAttributeEnabled) {
+    mozilla::net::ReferrerPolicy imgReferrerPolicy = GetImageReferrerPolicy();
+    // if the image does not provide a referrer attribute, ignore this
+    if (imgReferrerPolicy != mozilla::net::RP_Unset) {
+      referrerPolicy = imgReferrerPolicy;
+    }
+  }
+
   // Not blocked. Do the load.
   nsRefPtr<imgRequestProxy>& req = PrepareNextRequest(aImageLoadType);
   nsIContent* content = AsContent();
-  nsresult rv;
   rv = nsContentUtils::LoadImage(aNewURI, aDocument,
                                  aDocument->NodePrincipal(),
                                  aDocument->GetDocumentURI(),
-                                 aDocument->GetReferrerPolicy(),
+                                 referrerPolicy,
                                  this, loadFlags,
                                  content->LocalName(),
                                  getter_AddRefs(req),
@@ -1586,3 +1599,11 @@ nsImageLoadingContent::ImageObserver::~ImageObserver()
   MOZ_COUNT_DTOR(ImageObserver);
   NS_CONTENT_DELETE_LIST_MEMBER(ImageObserver, this, mNext);
 }
+
+// Only HTMLInputElement.h overrides this for <img> tags
+// all other subclasses use this one, i.e. ignore referrer attributes
+mozilla::net::ReferrerPolicy
+nsImageLoadingContent::GetImageReferrerPolicy()
+{
+  return mozilla::net::RP_Unset;
+};