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

content/renderer/media/video_track_adapter.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_MEDIA_VIDEO_TRACK_ADAPTER_H_
 #define CONTENT_RENDERER_MEDIA_VIDEO_TRACK_ADAPTER_H_
 
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/time/time.h"
 #include "content/renderer/media/media_stream_video_track.h"
 #include "media/base/video_frame.h"
 
 namespace content {
 
 // VideoTrackAdapter is a helper class used by MediaStreamVideoSource used for
 // adapting the video resolution from a source implementation to the resolution
 // a track requires. Different tracks can have different resolution constraints.
 // The constraints can be set as max width and height as well as max and min
 // aspect ratio.
 // Video frames are delivered to a track using a VideoCaptureDeliverFrameCB on
 // the IO-thread.
 // Adaptations is done by wrapping the original media::VideoFrame in a new
 // media::VideoFrame with a new visible_rect and natural_size.
 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);
 
   // Register |track| to receive video frames in |frame_callback| with
   // 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.
   // Must be called on the IO-thread.
   void DeliverFrameOnIO(
       const scoped_refptr<media::VideoFrame>& frame,
       const media::VideoCaptureFormat& format,
       const base::TimeTicks& estimated_capture_time);
 
   const scoped_refptr<base::MessageLoopProxy>& io_message_loop() {
     DCHECK(thread_checker_.CalledOnValidThread());
     return io_message_loop_;
   }
 
  private:
   virtual ~VideoTrackAdapter();
   friend class base::RefCountedThreadSafe<VideoTrackAdapter>;
 
   void AddTrackOnIO(
       const MediaStreamVideoTrack* track,
       VideoCaptureDeliverFrameCB frame_callback,
       const gfx::Size& max_frame_size,
       double min_aspect_ratio,
       double max_aspect_ratio,
       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_;
 
   scoped_refptr<base::MessageLoopProxy> io_message_loop_;
 
   // |renderer_task_runner_| is used to ensure that
   // VideoCaptureDeliverFrameCB is released on the main render thread.
   scoped_refptr<base::SingleThreadTaskRunner> renderer_task_runner_;
 
   // VideoFrameResolutionAdapter is an inner class that is created on the main
   // render thread but operates on the IO-thread. It does the resolution
   // adaptation and delivers frames to all registered tracks on the IO-thread.
   class VideoFrameResolutionAdapter;
   typedef std::vector<scoped_refptr<VideoFrameResolutionAdapter> >
       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);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_VIDEO_TRACK_ADAPTER_H_