Bug 1341555 - Consolidate use of the MSG's AbstractMainThread, and stop having AbstractMainThread on MediaStreams. r=pehrsons

MozReview-Commit-ID: 5hGDQcfpH6a

dom/html/HTMLMediaElement.cpp

@@ -4869,8 +4869,7 @@ public:
     mBlocked(false),
     mFinished(false),
     mMutex(aName),
-    mPendingNotifyOutput(false),
-    mAbstractMainThread(aElement->AbstractMainThread())
+    mPendingNotifyOutput(false)
   {}
   void Forget()
   {
@@ -4938,14 +4937,12 @@ public:
         this,
         &StreamListener::DoNotifyUnblocked);
     }
-    aGraph->DispatchToMainThreadAfterStreamStateUpdate(mAbstractMainThread,
-                                                       event.forget());
+    aGraph->DispatchToMainThreadAfterStreamStateUpdate(event.forget());
   }
   virtual void NotifyHasCurrentData(MediaStreamGraph* aGraph) override
   {
     MutexAutoLock lock(mMutex);
     aGraph->DispatchToMainThreadAfterStreamStateUpdate(
-      mAbstractMainThread,
       NewRunnableMethod(
         "dom::HTMLMediaElement::StreamListener::DoNotifyHaveCurrentData",
         this,
@@ -4959,7 +4956,6 @@ public:
       return;
     mPendingNotifyOutput = true;
     aGraph->DispatchToMainThreadAfterStreamStateUpdate(
-      mAbstractMainThread,
       NewRunnableMethod("dom::HTMLMediaElement::StreamListener::DoNotifyOutput",
                         this,
                         &StreamListener::DoNotifyOutput));
@@ -4975,7 +4971,6 @@ private:
   // mMutex protects the fields below; they can be accessed on any thread
   Mutex mMutex;
   bool mPendingNotifyOutput;
-  const RefPtr<AbstractThread> mAbstractMainThread;
 };
 
 class HTMLMediaElement::MediaStreamTracksAvailableCallback: