Change VideoRtpReceiver to create remote VideoTrack and VideoTrackSource.

webrtc/api/mediastreaminterface.h

Index: webrtc/api/mediastreaminterface.h
diff --git a/webrtc/api/mediastreaminterface.h b/webrtc/api/mediastreaminterface.h
index 54d3fd48c3be3451be643d2eb90f30be546ce840..69a50c97a3311b0e3259be0ea638e932e33e47dc 100644
--- a/webrtc/api/mediastreaminterface.h
+++ b/webrtc/api/mediastreaminterface.h
@@ -177,26 +177,6 @@ class VideoTrackInterface
 
   virtual VideoTrackSourceInterface* GetSource() const = 0;
 
-  // Return the track input sink. I.e., frames sent to this sink are
-  // propagated to all renderers registered with the track. The
-  // returned sink must not change between calls. Currently, this
-  // method is used for remote tracks (VideoRtpReceiver); further
-  // refactoring is planned for this path, it's unclear if this method
-  // belongs here long term.
-
-  // We do this instead of simply implementing the
-  // VideoSourceInterface directly, because if we did the latter, we'd
-  // need an OnFrame method in VideoTrackProxy, with a thread jump on
-  // each call.
-
-  // TODO(nisse): It has a default implementation so that mock
-  // objects, in particular, chrome's MockWebRtcVideoTrack, doesn't
-  // need to know about it. Consider removing the implementation (or
-  // this comment) after refactoring dust settles.
-  virtual rtc::VideoSinkInterface<cricket::VideoFrame>* GetSink() {
-    return nullptr;
-  };
-
  protected:
   virtual ~VideoTrackInterface() {}
 };