Bug 1365520. P1 - remove MDSM::mSentLoadedMetadataEvent and MDSM::EnqueueLoadedMetadataEvent(). r=kaku

The current call flow ensures decoding metadata only happens at most once
and therefore EnqueueLoadedMetadataEvent() will only be called at most once.
We don't need the mSentLoadedMetadataEvent flag.

MozReview-Commit-ID: E95jtRrKupw

--HG--
extra : rebase_source : b95887154a2392ca5a6fcb45b4c2dad60fb65b70

dom/media/MediaDecoderStateMachine.cpp

@@ -2166,7 +2166,10 @@ DecodeMetadataState::OnMetadataRead(MetadataHolder* aMetadata)
 
   MOZ_ASSERT(mMaster->mDuration.Ref().isSome());
 
-  mMaster->EnqueueLoadedMetadataEvent();
+  mMaster->mMetadataLoadedEvent.Notify(
+    nsAutoPtr<MediaInfo>(new MediaInfo(aMetadata->mInfo)),
+    Move(mMaster->mMetadataTags),
+    MediaDecoderEventVisibility::Observable);
 
   if (Info().IsEncrypted() && !mMaster->mCDMProxy) {
     // Metadata parsing was successful but we're still waiting for CDM caps
@@ -2681,7 +2684,6 @@ MediaDecoderStateMachine::MediaDecoderStateMachine(MediaDecoder* aDecoder,
   mAmpleAudioThreshold(detail::AMPLE_AUDIO_THRESHOLD),
   mAudioCaptured(false),
   mMinimizePreroll(aDecoder->GetMinimizePreroll()),
-  mSentLoadedMetadataEvent(false),
   mSentFirstFrameLoadedEvent(false),
   mVideoDecodeSuspended(false),
   mVideoDecodeSuspendTimer(mTaskQueue),
@@ -3466,19 +3468,6 @@ MediaDecoderStateMachine::DecodeError(const MediaResult& aError)
   mOnPlaybackErrorEvent.Notify(aError);
 }
 
-void
-MediaDecoderStateMachine::EnqueueLoadedMetadataEvent()
-{
-  MOZ_ASSERT(OnTaskQueue());
-  MediaDecoderEventVisibility visibility =
-    mSentLoadedMetadataEvent ? MediaDecoderEventVisibility::Suppressed
-                             : MediaDecoderEventVisibility::Observable;
-  mMetadataLoadedEvent.Notify(nsAutoPtr<MediaInfo>(new MediaInfo(Info())),
-                              Move(mMetadataTags),
-                              visibility);
-  mSentLoadedMetadataEvent = true;
-}
-
 void
 MediaDecoderStateMachine::EnqueueFirstFrameLoadedEvent()
 {

dom/media/MediaDecoderStateMachine.h

@@ -423,11 +423,6 @@ protected:
   // decode thread.
   void DecodeError(const MediaResult& aError);
 
-  // Dispatches a LoadedMetadataEvent.
-  // This is threadsafe and can be called on any thread.
-  // The decoder monitor must be held.
-  void EnqueueLoadedMetadataEvent();
-
   void EnqueueFirstFrameLoadedEvent();
 
   // Start a task to decode audio.
@@ -640,10 +635,6 @@ private:
 
   mozilla::MediaMetadataManager mMetadataManager;
 
-  // True if we are back from DECODER_STATE_DORMANT state and
-  // LoadedMetadataEvent was already sent.
-  bool mSentLoadedMetadataEvent;
-
   // True if we've decoded first frames (thus having the start time) and
   // notified the FirstFrameLoaded event. Note we can't initiate seek until the
   // start time is known which happens when the first frames are decoded or we