Make cricket::VideoCapturer implement VideoSourceInterface

talk/app/webrtc/rtpsender.h

 /*
  * libjingle
  * Copyright 2015 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 167 matching lines @@
  private:
   bool can_send_track() const { return track_ && ssrc_; }
   // Helper function to construct options for
   // VideoProviderInterface::SetVideoSend.
   void SetVideoSend();
 
   std::string id_;
   std::string stream_id_;
   VideoProviderInterface* provider_;
   rtc::scoped_refptr<VideoTrackInterface> track_;
+  // The sink registered with the current track_, if any.
+  rtc::VideoSinkInterface<cricket::VideoFrame>* sink_;
   uint32_t ssrc_ = 0;
   bool cached_track_enabled_ = false;
   bool stopped_ = false;
 };
 
 }  // namespace webrtc
 
 #endif  // TALK_APP_WEBRTC_RTPSENDER_H_