Bug 1209864. Part 1 - make all methods run on the main thread and remove usage of the decoder monitor. r=roc.

dom/media/MediaDecoderStateMachine.cpp

@@ -223,6 +223,7 @@ MediaDecoderStateMachine::MediaDecoderStateMachine(MediaDecoder* aDecoder,
   mSentPlaybackEndedEvent(false),
   mStreamSink(new DecodedStream(mTaskQueue, mAudioQueue, mVideoQueue)),
   mResource(aDecoder->GetResource()),
+  mAudioOffloading(false),
   mBuffered(mTaskQueue, TimeIntervals(),
             "MediaDecoderStateMachine::mBuffered (Mirror)"),
   mEstimatedDuration(mTaskQueue, NullableTimeUnit(),
@@ -1088,15 +1089,13 @@ void MediaDecoderStateMachine::MaybeStartPlayback()
   }
 
   bool playStatePermits = mPlayState == MediaDecoder::PLAY_STATE_PLAYING;
-  if (!playStatePermits || mIsAudioPrerolling || mIsVideoPrerolling) {
+  if (!playStatePermits || mIsAudioPrerolling ||
+      mIsVideoPrerolling || mAudioOffloading) {
     DECODER_LOG("Not starting playback [playStatePermits: %d, "
-                "mIsAudioPrerolling: %d, mIsVideoPrerolling: %d]",
-                (int) playStatePermits, (int) mIsAudioPrerolling, (int) mIsVideoPrerolling);
-    return;
-  }
-
-  if (mDecoder->CheckDecoderCanOffloadAudio()) {
-    DECODER_LOG("Offloading playback");
+                "mIsAudioPrerolling: %d, mIsVideoPrerolling: %d, "
+                "mAudioOffloading: %d]",
+                (int)playStatePermits, (int)mIsAudioPrerolling,
+                (int)mIsVideoPrerolling, (int)mAudioOffloading);
     return;
   }
 

dom/media/MediaDecoderStateMachine.h

@@ -205,6 +205,19 @@ public:
     OwnerThread()->Dispatch(r.forget());
   }
 
+  void DispatchAudioOffloading(bool aAudioOffloading)
+  {
+    nsRefPtr<MediaDecoderStateMachine> self = this;
+    nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction([=] () {
+      ReentrantMonitorAutoEnter mon(self->mDecoder->GetReentrantMonitor());
+      if (self->mAudioOffloading != aAudioOffloading) {
+        self->mAudioOffloading = aAudioOffloading;
+        self->ScheduleStateMachine();
+      }
+    });
+    OwnerThread()->Dispatch(r.forget());
+  }
+
   // Drop reference to decoder.  Only called during shutdown dance.
   void BreakCycles() {
     MOZ_ASSERT(NS_IsMainThread());
@@ -1242,6 +1255,10 @@ private:
   MediaEventListener mAudioQueueListener;
   MediaEventListener mVideoQueueListener;
 
+  // True if audio is offloading.
+  // Playback will not start when audio is offloading.
+  bool mAudioOffloading;
+
 #ifdef MOZ_EME
   void OnCDMProxyReady(nsRefPtr<CDMProxy> aProxy);
   void OnCDMProxyNotReady();

dom/media/omx/MediaOmxCommonDecoder.cpp

@@ -41,13 +41,38 @@ MediaOmxCommonDecoder::~MediaOmxCommonDecoder() {}
 void
 MediaOmxCommonDecoder::SetPlatformCanOffloadAudio(bool aCanOffloadAudio)
 {
-  ReentrantMonitorAutoEnter mon(GetReentrantMonitor());
-  mCanOffloadAudio = aCanOffloadAudio;
+  if (!aCanOffloadAudio) {
+    return;
+  }
+
+  // Stop MDSM from playing to avoid startup glitch (bug 1053186).
+  GetStateMachine()->DispatchAudioOffloading(true);
+
+  // Modify mCanOffloadAudio in the main thread.
+  nsRefPtr<MediaOmxCommonDecoder> self = this;
+  nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction([=] () {
+    self->mCanOffloadAudio = true;
+  });
+  AbstractThread::MainThread()->Dispatch(r.forget());
+}
+
+void
+MediaOmxCommonDecoder::DisableStateMachineAudioOffloading()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  if (mCanOffloadAudio) {
+    // mCanOffloadAudio is true implies we've called
+    // |GetStateMachine()->DispatchAudioOffloading(true)| in
+    // SetPlatformCanOffloadAudio(). We need to turn off audio offloading
+    // for MDSM so it can start playback.
+    GetStateMachine()->DispatchAudioOffloading(false);
+  }
 }
 
 bool
 MediaOmxCommonDecoder::CheckDecoderCanOffloadAudio()
 {
+  MOZ_ASSERT(NS_IsMainThread());
   return (mCanOffloadAudio && !mFallbackToStateMachine &&
           !mIsCaptured && mPlaybackRate == 1.0);
 }
@@ -64,10 +89,10 @@ MediaOmxCommonDecoder::FirstFrameLoaded(nsAutoPtr<MediaInfo> aInfo,
 
   MediaDecoder::FirstFrameLoaded(aInfo, aEventVisibility);
 
-  ReentrantMonitorAutoEnter mon(GetReentrantMonitor());
   if (!CheckDecoderCanOffloadAudio()) {
     DECODER_LOG(LogLevel::Debug, ("In %s Offload Audio check failed",
         __PRETTY_FUNCTION__));
+    DisableStateMachineAudioOffloading();
     return;
   }
 
@@ -75,6 +100,7 @@ MediaOmxCommonDecoder::FirstFrameLoaded(nsAutoPtr<MediaInfo> aInfo,
   mAudioOffloadPlayer = new AudioOffloadPlayer(this);
 #endif
   if (!mAudioOffloadPlayer) {
+    DisableStateMachineAudioOffloading();
     return;
   }
 
@@ -85,6 +111,7 @@ MediaOmxCommonDecoder::FirstFrameLoaded(nsAutoPtr<MediaInfo> aInfo,
     mFallbackToStateMachine = true;
     DECODER_LOG(LogLevel::Debug, ("In %s Unable to start offload audio %d."
       "Switching to normal mode", __PRETTY_FUNCTION__, err));
+    DisableStateMachineAudioOffloading();
     return;
   }
   PauseStateMachine();
@@ -105,7 +132,6 @@ void
 MediaOmxCommonDecoder::PauseStateMachine()
 {
   MOZ_ASSERT(NS_IsMainThread());
-  GetReentrantMonitor().AssertCurrentThreadIn();
   DECODER_LOG(LogLevel::Debug, ("%s", __PRETTY_FUNCTION__));
 
   if (mShuttingDown) {
@@ -123,7 +149,6 @@ void
 MediaOmxCommonDecoder::ResumeStateMachine()
 {
   MOZ_ASSERT(NS_IsMainThread());
-  ReentrantMonitorAutoEnter mon(GetReentrantMonitor());
   DECODER_LOG(LogLevel::Debug, ("%s current time %f", __PRETTY_FUNCTION__, mLogicalPosition));
 
   if (mShuttingDown) {
@@ -134,6 +159,8 @@ MediaOmxCommonDecoder::ResumeStateMachine()
     return;
   }
 
+  GetStateMachine()->DispatchAudioOffloading(false);
+
   mFallbackToStateMachine = true;
   mAudioOffloadPlayer = nullptr;
   SeekTarget target = SeekTarget(mLogicalPosition,
@@ -231,8 +258,6 @@ MediaOmxCommonDecoder::CurrentPosition()
   if (!mAudioOffloadPlayer) {
     return MediaDecoder::CurrentPosition();
   }
-
-  ReentrantMonitorAutoEnter mon(GetReentrantMonitor());
   return mAudioOffloadPlayer->GetMediaTimeUs();
 }
 

dom/media/omx/MediaOmxCommonDecoder.h

@@ -50,6 +50,7 @@ protected:
   virtual ~MediaOmxCommonDecoder();
   void PauseStateMachine();
   void ResumeStateMachine();
+  void DisableStateMachineAudioOffloading();
 
   MediaOmxCommonReader* mReader;