Bug 1173001 - Enable tail dispatch for the decode task queue. r=jww

dom/media/MediaDecoderReader.cpp

@@ -64,7 +64,9 @@ MediaDecoderReader::MediaDecoderReader(AbstractMediaDecoder* aDecoder,
                                        MediaTaskQueue* aBorrowedTaskQueue)
   : mAudioCompactor(mAudioQueue)
   , mDecoder(aDecoder)
-  , mTaskQueue(aBorrowedTaskQueue ? aBorrowedTaskQueue : new MediaTaskQueue(GetMediaThreadPool(MediaThreadType::PLAYBACK)))
+  , mTaskQueue(aBorrowedTaskQueue ? aBorrowedTaskQueue
+                                  : new MediaTaskQueue(GetMediaThreadPool(MediaThreadType::PLAYBACK),
+                                                       /* aSupportsTailDispatch = */ true))
   , mIgnoreAudioOutputFormat(false)
   , mStartTime(-1)
   , mHitAudioDecodeError(false)

dom/media/MediaDecoderStateMachine.cpp

@@ -182,7 +182,7 @@ MediaDecoderStateMachine::MediaDecoderStateMachine(MediaDecoder* aDecoder,
                                                    bool aRealTime) :
   mDecoder(aDecoder),
   mTaskQueue(new MediaTaskQueue(GetMediaThreadPool(MediaThreadType::PLAYBACK),
-                                /* aAssertTailDispatch = */ true)),
+                                /* aSupportsTailDispatch = */ true)),
   mWatchManager(this, mTaskQueue),
   mRealTime(aRealTime),
   mDispatchedStateMachine(false),

dom/media/MediaTaskQueue.h

@@ -31,7 +31,7 @@ typedef MediaPromise<bool, bool, false> ShutdownPromise;
 // to make this threadsafe for objects that aren't already threadsafe.
 class MediaTaskQueue : public AbstractThread {
 public:
-  explicit MediaTaskQueue(TemporaryRef<SharedThreadPool> aPool, bool aRequireTailDispatch = false);
+  explicit MediaTaskQueue(TemporaryRef<SharedThreadPool> aPool, bool aSupportsTailDispatch = false);
 
   void Dispatch(TemporaryRef<nsIRunnable> aRunnable,
                 DispatchFailureHandling aFailureHandling = AssertDispatchSuccess)