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..8a719ec0b43bb43f8c2cf23345d9dfedd3c7e097 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.
+  // |target_frame_rate| is used to calculate a prudent interval to check for

[Henrik Grunell, 2014/07/09 08:55:53]

I think the naming of |target_frame_rate| is not clear, at least not to me. :)
I'd interpret "target" as something this class would (try to) adapt to, but it's
actually a monitor interval. Would "monitor_interval_frame_rate" be a correct
description?

[Henrik Grunell, 2014/07/09 13:01:22]

I guess you missed a reply on this, |source_frame_rate| is better, thanks.

+  // passing frames and inform of the result via |on_muted_state_callback|.

[Henrik Grunell, 2014/07/09 08:55:52]

It only informs via the callback if we consider it muted, right? Clarify that.

[mcasas, 2014/07/09 12:39:35]

It pings back every time it wakes up, with the 
appropriate state every time.

[Henrik Grunell, 2014/07/09 13:01:22]

Oh, right.

   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 target_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 target_frame_rate);
+
+  // Compare |frame_counter_snapshot| with the current |frame_counter_|, and
+  // inform of the situation via |set_muted_state_callback|.

[Henrik Grunell, 2014/07/09 08:55:53]

Same as above. Clarify only if considered muted.

[mcasas, 2014/07/09 12:39:35]

Done.

+  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 +99,11 @@ class VideoTrackAdapter
       FrameAdapters;
   FrameAdapters adapters_;
 
+  // Running frame_counter, accesed on IO-thread.

[Henrik Grunell, 2014/07/09 08:55:52]

"Running frame counter, accessed on the IO-thread."

[mcasas, 2014/07/09 12:39:35]

Done.

+  uint64 frame_counter_;
+  // Frame rate configured on the source, accesed on IO-thread.

[Henrik Grunell, 2014/07/09 08:55:52]

Nit: add empty line before.

[Henrik Grunell, 2014/07/09 08:55:53]

I don't understand the "configured on the source" part.
Nit: "accessed on the"

[mcasas, 2014/07/09 12:39:35]

Done.

[mcasas, 2014/07/09 12:39:35]

Done.

+  float target_frame_rate_;

[Henrik Grunell, 2014/07/09 08:55:53]

Same as above, for me the "target" part of the name is unclear.

[mcasas, 2014/07/09 12:39:35]

See above.

+
   DISALLOW_COPY_AND_ASSIGN(VideoTrackAdapter);
 };