Refactor VideoTracks to forward all sinks to its source

webrtc/media/base/videobroadcaster.h

Index: webrtc/media/base/videobroadcaster.h
diff --git a/webrtc/media/base/videobroadcaster.h b/webrtc/media/base/videobroadcaster.h
index b4227eaba6f314fe65f73492be7ae5d1b43ea4c8..c89c7eea9753082a1a76f456f01a67f69a842955 100644
--- a/webrtc/media/base/videobroadcaster.h
+++ b/webrtc/media/base/videobroadcaster.h
@@ -18,7 +18,8 @@
 #include "webrtc/base/thread_checker.h"
 #include "webrtc/media/base/videoframe.h"
 #include "webrtc/media/base/videosinkinterface.h"
-#include "webrtc/media/base/videosourceinterface.h"
+#include "webrtc/media/base/videosourcebase.h"
+#include "webrtc/media/engine/webrtcvideoframe.h"
 
 namespace rtc {
 
@@ -28,7 +29,7 @@ namespace rtc {
 // Sinks must be added and removed on one and only one thread.
 // Video frames can be broadcasted on any thread. I.e VideoBroadcaster::OnFrame
 // can be called on any thread.
-class VideoBroadcaster : public VideoSourceInterface<cricket::VideoFrame>,
+class VideoBroadcaster : public VideoSourceBase,
                          public VideoSinkInterface<cricket::VideoFrame> {
  public:
   VideoBroadcaster();
@@ -46,22 +47,15 @@ class VideoBroadcaster : public VideoSourceInterface<cricket::VideoFrame>,
   void OnFrame(const cricket::VideoFrame& frame) override;
 
  protected:
-  struct SinkPair {
-    SinkPair(VideoSinkInterface<cricket::VideoFrame>* sink,
-             VideoSinkWants wants)
-        : sink(sink), wants(wants) {}
-    VideoSinkInterface<cricket::VideoFrame>* sink;
-    VideoSinkWants wants;
-  };
-  SinkPair* FindSinkPair(const VideoSinkInterface<cricket::VideoFrame>* sink)
-      EXCLUSIVE_LOCKS_REQUIRED(sinks_and_wants_lock_);
   void UpdateWants() EXCLUSIVE_LOCKS_REQUIRED(sinks_and_wants_lock_);
+  const cricket::VideoFrame& GetBlackFrame(const cricket::VideoFrame& frame)
+      EXCLUSIVE_LOCKS_REQUIRED(sinks_and_wants_lock_);
 
   ThreadChecker thread_checker_;
   rtc::CriticalSection sinks_and_wants_lock_;
 
   VideoSinkWants current_wants_ GUARDED_BY(sinks_and_wants_lock_);
-  std::vector<SinkPair> sinks_ GUARDED_BY(sinks_and_wants_lock_);
+  rtc::scoped_ptr<cricket::WebRtcVideoFrame> black_frame_;
 };
 
 }  // namespace rtc