Bug 1296531 - Remove MediaStream blocking logic from HTMLMediaElement. r=jesup

MediaStreamGraph only implements the blocking notifications for SourceMediaStreams,
but the MediaStream that gets attached as srcObject on a media element is always
a TrackUnionStream. Hence, this code is unused and can be removed.

MozReview-Commit-ID: 6DKtCGNsZec

dom/html/HTMLMediaElement.cpp

@@ -4892,7 +4892,6 @@ public:
     WatchTarget(aName),
     mElement(aElement),
     mHaveCurrentData(false),
-    mBlocked(false),
     mFinished(false),
     mMutex(aName),
     mPendingNotifyOutput(false)
@@ -4910,21 +4909,9 @@ public:
     if (!mElement || !mHaveCurrentData || mFinished) {
       return MediaDecoderOwner::NEXT_FRAME_UNAVAILABLE;
     }
-    return mBlocked
-        ? MediaDecoderOwner::NEXT_FRAME_UNAVAILABLE_BUFFERING
-        : MediaDecoderOwner::NEXT_FRAME_AVAILABLE;
+    return MediaDecoderOwner::NEXT_FRAME_AVAILABLE;
   }
 
-  void DoNotifyBlocked()
-  {
-    mBlocked = true;
-    NotifyWatchers();
-  }
-  void DoNotifyUnblocked()
-  {
-    mBlocked = false;
-    NotifyWatchers();
-  }
   void DoNotifyOutput()
   {
     {
@@ -4949,22 +4936,6 @@ public:
 
   // These notifications run on the media graph thread so we need to
   // dispatch events to the main thread.
-  virtual void NotifyBlockingChanged(MediaStreamGraph* aGraph, Blocking aBlocked) override
-  {
-    nsCOMPtr<nsIRunnable> event;
-    if (aBlocked == BLOCKED) {
-      event = NewRunnableMethod(
-        "dom::HTMLMediaElement::StreamListener::DoNotifyBlocked",
-        this,
-        &StreamListener::DoNotifyBlocked);
-    } else {
-      event = NewRunnableMethod(
-        "dom::HTMLMediaElement::StreamListener::DoNotifyUnblocked",
-        this,
-        &StreamListener::DoNotifyUnblocked);
-    }
-    aGraph->DispatchToMainThreadAfterStreamStateUpdate(event.forget());
-  }
   virtual void NotifyHasCurrentData(MediaStreamGraph* aGraph) override
   {
     MutexAutoLock lock(mMutex);
@@ -4991,7 +4962,6 @@ private:
   // These fields may only be accessed on the main thread
   HTMLMediaElement* mElement;
   bool mHaveCurrentData;
-  bool mBlocked;
   bool mFinished;
 
   // mMutex protects the fields below; they can be accessed on any thread