Added mute logic to VideoTrackRenderers.

talk/app/webrtc/test/fakevideotrackrenderer.h

 /*
  * libjingle
  * Copyright 2012 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 39 matching lines @@
                                 0)) {
       return;
     }
 
     fake_renderer_.RenderFrame(video_frame);
   }
 
   int errors() const { return fake_renderer_.errors(); }
   int width() const { return fake_renderer_.width(); }
   int height() const { return fake_renderer_.height(); }
+  bool black_frame() const { return fake_renderer_.black_frame(); }
+
   int num_rendered_frames() const {
     return fake_renderer_.num_rendered_frames();
   }
   const cricket::VideoFrame* last_frame() const { return last_frame_; }
 
  private:
   cricket::FakeVideoRenderer fake_renderer_;
   rtc::scoped_refptr<VideoTrackInterface> video_track_;
 
   // Weak reference for frame pointer comparison only.
   cricket::VideoFrame* last_frame_;
 };
 
 }  // namespace webrtc
 
 #endif  // TALK_APP_WEBRTC_TEST_FAKEVIDEOTRACKRENDERER_H_