Introduce TimeSource notifications to the VideoRenderer.

media/renderers/video_renderer_impl.h

Index: media/renderers/video_renderer_impl.h
diff --git a/media/renderers/video_renderer_impl.h b/media/renderers/video_renderer_impl.h
index ec3d72d2714ff811c0d88c2a8dc57fc3197bef90..0c7c2162fc584f72410d70a4168ae0c44fde3e34 100644
--- a/media/renderers/video_renderer_impl.h
+++ b/media/renderers/video_renderer_impl.h
@@ -71,6 +71,10 @@ class MEDIA_EXPORT VideoRendererImpl
 
   void SetTickClockForTesting(scoped_ptr<base::TickClock> tick_clock);
 
+  // TimeSourceDependent implementation.
+  void OnTimeProgressing() override;
+  void OnTimeStopped() override;
+
  private:
   // Creates a dedicated |thread_| for video rendering.
   void CreateVideoThread();