VideoTrackAdapter: Add passing frames monitor, notify MSVCS -> MSVTrack(s)

content/renderer/media/media_stream_track.h

Index: content/renderer/media/media_stream_track.h
diff --git a/content/renderer/media/media_stream_track.h b/content/renderer/media/media_stream_track.h
index 456005d4d054284e2a999187c5375c171a468369..fbd220bbd92eb03ade79e8f2d4396905d46d0c86 100644
--- a/content/renderer/media/media_stream_track.h
+++ b/content/renderer/media/media_stream_track.h
@@ -34,6 +34,9 @@ class CONTENT_EXPORT MediaStreamTrack
   // If a subclass overrides this method it has to call the base class.
   virtual void SetEnabled(bool enabled);
 
+  virtual void SetMutedState(bool muted_state);
+  virtual bool GetMutedState(void) const;

[Henrik Grunell, 2014/07/10 08:41:34]

bool muted_state() const { return muted_state_; }

Or does it need to be virtual?
Does SetMutedState?

[mcasas, 2014/07/10 11:59:04]

Discussed offline, but just to get it logged:

MSTrack is a parent class of MSVideoTrack and
MSAudioTrack (actually WebRtcLocalAudioTrack).
WebRtcLocalAudioTrack knows not of |muted_state|
hence the local implementation here.

As per W3C doco, all tracks should implement 
the muted event, so there's a default 
implementation here, just not using the 
standard mutator and accessor naming because
the deriving classes might -and actually do- 
more stuff, in MSVT case, checks the thread.

+
   // TODO(xians): Make this pure virtual when Stop[Track] has been
   // implemented for remote audio tracks.
   virtual void Stop();
@@ -45,6 +48,9 @@ class CONTENT_EXPORT MediaStreamTrack
  protected:
   scoped_refptr<webrtc::MediaStreamTrackInterface> track_;
 
+  // Set to true if the owner MediaStreamSource is not delivering frames.
+  bool muted_state_;
+
  private:
   const bool is_local_track_;