Add MediaStreamSource frame rate calculation to the tracker.

content/renderer/media/media_stream_video_source.h

Index: content/renderer/media/media_stream_video_source.h
diff --git a/content/renderer/media/media_stream_video_source.h b/content/renderer/media/media_stream_video_source.h
index d1ceeefa66323e87c91a3759ae78596a82ad6770..f1bd002e7472a197fa2e0415fe969cd0a2e784ce 100644
--- a/content/renderer/media/media_stream_video_source.h
+++ b/content/renderer/media/media_stream_video_source.h
@@ -90,7 +90,7 @@ class CONTENT_EXPORT MediaStreamVideoSource
   virtual void SetReadyState(blink::WebMediaStreamSource::ReadyState state);
 
   // Sets muted state and notifies it to all registered tracks.
-  virtual void SetMutedState(bool state);
+  virtual void OnFrameRateCallback(float framerate, int dropped_frames);
 
   // An implementation must fetch the formats that can currently be used by
   // the source and call OnSupportedFormats when done.
@@ -118,6 +118,8 @@ class CONTENT_EXPORT MediaStreamVideoSource
   // method has been called, MediaStreamVideoSource may be deleted.
   virtual void StopSourceImpl() = 0;
 
+  virtual std::string TypeName() const;
+
   enum State {
     NEW,
     RETRIEVING_CAPABILITIES,