Bug 1224973 - Part 3: Plumb element visibility into MDSM. r=jya,jwwang

change MediaDecoder::mIsVisible to be a Canonical<bool> and plumb through to
the MediaDecoderStateMachine.  This will be used to trigger suspending the
decoding of video frames.

MozReview-Commit-ID: F3Dpf0ogE7c

dom/media/AbstractMediaDecoder.h

@@ -62,7 +62,7 @@ public:
 
   // Return an event that will be notified when data arrives in MediaResource.
   // MediaDecoderReader will register with this event to receive notifications
-  // in order to udpate buffer ranges.
+  // in order to update buffer ranges.
   // Return null if this decoder doesn't support the event.
   virtual MediaEventSource<void>* DataArrivedEvent()
   {

dom/media/MediaDecoder.cpp

@@ -335,7 +335,7 @@ MediaDecoder::UpdateDormantState(bool aDormantTimeout, bool aActivity)
               "ownerActive=%d mIsVisible=%d mIsHeuristicDormant=%d "
               "mPlayState=%s encrypted=%s",
               aDormantTimeout, aActivity, mIsDormant, mOwner->IsActive(),
-              mIsVisible, mIsHeuristicDormant, PlayStateStr(),
+              mIsVisible.Ref(), mIsHeuristicDormant, PlayStateStr(),
               (!mInfo ? "Unknown" : (mInfo->IsEncrypted() ? "1" : "0")));
 
   bool prevDormant = mIsDormant;
@@ -574,7 +574,8 @@ MediaDecoder::MediaDecoder(MediaDecoderOwner* aOwner)
                    "MediaDecoder::mMediaSeekable (Canonical)")
   , mMediaSeekableOnlyInBufferedRanges(AbstractThread::MainThread(), false,
                    "MediaDecoder::mMediaSeekableOnlyInBufferedRanges (Canonical)")
-  , mIsVisible(!mOwner->IsHidden())
+  , mIsVisible(AbstractThread::MainThread(), !mOwner->IsHidden(),
+               "MediaDecoder::mIsVisible (Canonical)")
   , mTelemetryReported(false)
 {
   MOZ_COUNT_CTOR(MediaDecoder);

dom/media/MediaDecoder.h

@@ -744,7 +744,7 @@ protected:
   // start playing back again.
   Mirror<int64_t> mPlaybackPosition;
 
-  // Used to distiguish whether the audio is producing sound.
+  // Used to distinguish whether the audio is producing sound.
   Mirror<bool> mIsAudioDataAudible;
 
   // Volume of playback.  0.0 = muted. 1.0 = full volume.
@@ -806,7 +806,8 @@ protected:
   // True if the media is only seekable within its buffered ranges.
   Canonical<bool> mMediaSeekableOnlyInBufferedRanges;
 
-  bool mIsVisible;
+  // True if the decoder is visible.
+  Canonical<bool> mIsVisible;
 
 public:
   AbstractCanonical<media::NullableTimeUnit>* CanonicalDurationOrNull() override;
@@ -855,6 +856,9 @@ public:
   AbstractCanonical<bool>* CanonicalMediaSeekableOnlyInBufferedRanges() {
     return &mMediaSeekableOnlyInBufferedRanges;
   }
+  AbstractCanonical<bool>* CanonicalIsVisible() {
+    return &mIsVisible;
+  }
 
 private:
   // Notify owner when the audible state changed

dom/media/MediaDecoderReader.cpp

@@ -183,6 +183,10 @@ MediaDecoderReader::UpdateBuffered()
   mBuffered = GetBuffered();
 }
 
+void
+MediaDecoderReader::VisibilityChanged()
+{}
+
 media::TimeIntervals
 MediaDecoderReader::GetBuffered()
 {

dom/media/MediaDecoderReader.h

@@ -395,6 +395,8 @@ private:
   // Recomputes mBuffered.
   virtual void UpdateBuffered();
 
+  virtual void VisibilityChanged();
+
   virtual void NotifyDataArrivedInternal() {}
 
   // Overrides of this function should decodes an unspecified amount of

dom/media/MediaDecoderStateMachine.cpp

@@ -271,6 +271,7 @@ MediaDecoderStateMachine::MediaDecoderStateMachine(MediaDecoder* aDecoder,
                  "MediaDecoderStateMachine::mMediaSeekable (Mirror)"),
   mMediaSeekableOnlyInBufferedRanges(mTaskQueue, false,
                  "MediaDecoderStateMachine::mMediaSeekableOnlyInBufferedRanges (Mirror)"),
+  mIsVisible(mTaskQueue, true, "MediaDecoderStateMachine::mIsVisible (Mirror)"),
   mDuration(mTaskQueue, NullableTimeUnit(),
             "MediaDecoderStateMachine::mDuration (Canonical"),
   mIsShutdown(mTaskQueue, false,
@@ -333,6 +334,7 @@ MediaDecoderStateMachine::InitializationTask(MediaDecoder* aDecoder)
   mDecoderPosition.Connect(aDecoder->CanonicalDecoderPosition());
   mMediaSeekable.Connect(aDecoder->CanonicalMediaSeekable());
   mMediaSeekableOnlyInBufferedRanges.Connect(aDecoder->CanonicalMediaSeekableOnlyInBufferedRanges());
+  mIsVisible.Connect(aDecoder->CanonicalIsVisible());
 
   // Initialize watchers.
   mWatchManager.Watch(mBuffered, &MediaDecoderStateMachine::BufferedRangeUpdated);
@@ -346,6 +348,7 @@ MediaDecoderStateMachine::InitializationTask(MediaDecoder* aDecoder)
   mWatchManager.Watch(mExplicitDuration, &MediaDecoderStateMachine::RecomputeDuration);
   mWatchManager.Watch(mObservedDuration, &MediaDecoderStateMachine::RecomputeDuration);
   mWatchManager.Watch(mPlayState, &MediaDecoderStateMachine::PlayStateChanged);
+  mWatchManager.Watch(mIsVisible, &MediaDecoderStateMachine::VisibilityChanged);
 
   // Configure MediaDecoderReaderWrapper.
   SetMediaDecoderReaderWrapperCallback();
@@ -1312,6 +1315,11 @@ void MediaDecoderStateMachine::PlayStateChanged()
   ScheduleStateMachine();
 }
 
+void MediaDecoderStateMachine::VisibilityChanged()
+{
+  DECODER_LOG("VisibilityChanged: is visible = %c", mIsVisible ? 'T' : 'F');
+}
+
 void MediaDecoderStateMachine::BufferedRangeUpdated()
 {
   MOZ_ASSERT(OnTaskQueue());
@@ -2085,6 +2093,7 @@ MediaDecoderStateMachine::FinishShutdown()
   mDecoderPosition.DisconnectIfConnected();
   mMediaSeekable.DisconnectIfConnected();
   mMediaSeekableOnlyInBufferedRanges.DisconnectIfConnected();
+  mIsVisible.DisconnectIfConnected();
 
   mDuration.DisconnectAll();
   mIsShutdown.DisconnectAll();

dom/media/MediaDecoderStateMachine.h

@@ -471,6 +471,9 @@ protected:
   // Notification method invoked when mPlayState changes.
   void PlayStateChanged();
 
+  // Notification method invoked when mIsVisible changes.
+  void VisibilityChanged();
+
   // Sets internal state which causes playback of media to pause.
   // The decoder monitor must be held.
   void StopPlayback();
@@ -997,6 +1000,9 @@ private:
   // True if the media is seekable only in buffered ranges.
   Mirror<bool> mMediaSeekableOnlyInBufferedRanges;
 
+  // IsVisible, mirrored from the media decoder.
+  Mirror<bool> mIsVisible;
+
   // Duration of the media. This is guaranteed to be non-null after we finish
   // decoding the first frame.
   Canonical<media::NullableTimeUnit> mDuration;
@@ -1016,7 +1022,7 @@ private:
   // Current playback position in the stream in bytes.
   Canonical<int64_t> mPlaybackOffset;
 
-  // Used to distiguish whether the audio is producing sound.
+  // Used to distinguish whether the audio is producing sound.
   Canonical<bool> mIsAudioDataAudible;
 
 public: