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

content/renderer/media/video_track_adapter.h

Index: content/renderer/media/video_track_adapter.h
diff --git a/content/renderer/media/video_track_adapter.h b/content/renderer/media/video_track_adapter.h
index 0df314d279933fcd6bccb8623a051f845dec71b1..c26ca142981f7335469c4af6d2240d3279495208 100644
--- a/content/renderer/media/video_track_adapter.h
+++ b/content/renderer/media/video_track_adapter.h
@@ -27,6 +27,8 @@ namespace content {
 class VideoTrackAdapter
     : public base::RefCountedThreadSafe<VideoTrackAdapter> {
  public:
+  typedef base::Callback<void(bool mute_state)> OnMutedCallback;
+
   explicit VideoTrackAdapter(
       const scoped_refptr<base::MessageLoopProxy>& io_message_loop);
 
@@ -34,12 +36,16 @@ class VideoTrackAdapter
   // a resolution within the boundaries of the arguments.
   // Must be called on the main render thread. |frame_callback| is guaranteed to
   // be released on the main render thread.
+  // |source_frame_rate| is used to calculate a prudent interval to check for
+  // passing frames and inform of the result via |on_muted_state_callback|.
   void AddTrack(const MediaStreamVideoTrack* track,
                 VideoCaptureDeliverFrameCB frame_callback,
                 int max_width, int max_height,
                 double min_aspect_ratio,
                 double max_aspect_ratio,
-                double max_frame_rate);
+                double max_frame_rate,
+                double source_frame_rate,
+                const OnMutedCallback& on_muted_state_callback);
   void RemoveTrack(const MediaStreamVideoTrack* track);
 
   // Delivers |frame| to all tracks that have registered a callback.
@@ -67,6 +73,15 @@ class VideoTrackAdapter
       double max_frame_rate);
   void RemoveTrackOnIO(const MediaStreamVideoTrack* track);
 
+  void StartTrackMonitoringOnIO(
+    const OnMutedCallback& on_muted_state_callback,
+    double source_frame_rate);
+
+  // Compare |frame_counter_snapshot| with the current |frame_counter_|, and
+  // inform of the situation (muted, not muted) via |set_muted_state_callback|.
+  void CheckFramesReceivedOnIO(const OnMutedCallback& set_muted_state_callback,
+                               uint64 old_frame_counter_snapshot);
+
   // |thread_checker_| is bound to the main render thread.
   base::ThreadChecker thread_checker_;
 
@@ -84,6 +99,12 @@ class VideoTrackAdapter
       FrameAdapters;
   FrameAdapters adapters_;
 
+  // Running frame counter, accessed on the IO-thread.
+  uint64 frame_counter_;
+
+  // Frame rate configured on the video source, accessed on the IO-thread.
+  float source_frame_rate_;
+
   DISALLOW_COPY_AND_ASSIGN(VideoTrackAdapter);
 };