Bug 1069730 - Grab decoder monitor when clearing mEssentialTrackBuffers. r=cajbir

Also ensure MediaSource::InitializationEvent is only queued once.

content/media/mediasource/MediaSource.cpp

@@ -338,7 +338,7 @@ MediaSource::Detach()
   }
   mDecoder->DetachMediaSource();
   mDecoder = nullptr;
-  mFirstSourceBufferInitialization = false;
+  mFirstSourceBufferInitialized = false;
   SetReadyState(MediaSourceReadyState::Closed);
   mDuration = UnspecifiedNaN<double>();
   if (mActiveSourceBuffers) {
@@ -395,7 +395,7 @@ MediaSource::MediaSource(nsPIDOMWindow* aWindow)
   , mDuration(UnspecifiedNaN<double>())
   , mDecoder(nullptr)
   , mReadyState(MediaSourceReadyState::Closed)
-  , mFirstSourceBufferInitialization(false)
+  , mFirstSourceBufferInitialized(false)
 {
   MOZ_ASSERT(NS_IsMainThread());
   mSourceBuffers = new SourceBufferList(this);
@@ -487,9 +487,10 @@ void
 MediaSource::QueueInitializationEvent()
 {
   MOZ_ASSERT(NS_IsMainThread());
-  if (!mFirstSourceBufferInitialization) {
-    mFirstSourceBufferInitialization = true;
+  if (mFirstSourceBufferInitialized) {
+    return;
   }
+  mFirstSourceBufferInitialized = true;
   MSE_DEBUG("MediaSource(%p)::QueueInitializationEvent()", this);
   nsRefPtr<nsIRunnable> task =
     NS_NewRunnableMethod(this, &MediaSource::InitializationEvent);

content/media/mediasource/MediaSource.h

@@ -92,7 +92,7 @@ public:
 
   // Queue InitializationEvent to run on the main thread.  Called when a
   // SourceBuffer has an initialization segment appended, but only
-  // dispatched the first time (using mFirstSourceBufferInitialization).
+  // dispatched the first time (using mFirstSourceBufferInitialized).
   // Demarcates the point in time at which only currently registered
   // TrackBuffers are treated as essential by the MediaSourceReader for
   // initialization.
@@ -130,7 +130,7 @@ private:
 
   MediaSourceReadyState mReadyState;
 
-  bool mFirstSourceBufferInitialization;
+  bool mFirstSourceBufferInitialized;
 };
 
 NS_DEFINE_STATIC_IID_ACCESSOR(MediaSource, MOZILLA_DOM_MEDIASOURCE_IMPLEMENTATION_IID)

content/media/mediasource/MediaSourceReader.cpp

@@ -473,7 +473,10 @@ MediaSourceReader::ReadMetadata(MediaInfo* aInfo, MetadataTags** aTags)
             this, mEssentialTrackBuffers.Length(), mTrackBuffers.Length(),
             mAudioTrack.get(), mVideoTrack.get());
 
-  mEssentialTrackBuffers.Clear();
+  {
+    ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());
+    mEssentialTrackBuffers.Clear();
+  }
   if (!mAudioTrack && !mVideoTrack) {
     MSE_DEBUG("MediaSourceReader(%p)::ReadMetadata missing track: mAudioTrack=%p mVideoTrack=%p",
               this, mAudioTrack.get(), mVideoTrack.get());