Reland of Add framerate to VideoSinkWants and ability to signal on overuse

webrtc/media/engine/webrtcvideoengine2.h

Index: webrtc/media/engine/webrtcvideoengine2.h
diff --git a/webrtc/media/engine/webrtcvideoengine2.h b/webrtc/media/engine/webrtcvideoengine2.h
index 309a84d924d1474233587c8cbd420837427a95e6..0a2f4a5d86f71906b03939100812ba53aa7f2689 100644
--- a/webrtc/media/engine/webrtcvideoengine2.h
+++ b/webrtc/media/engine/webrtcvideoengine2.h
@@ -324,6 +324,9 @@ class WebRtcVideoChannel2 : public VideoMediaChannel, public webrtc::Transport {
     // and whether or not the encoding in |rtp_parameters_| is active.
     void UpdateSendState();
 
+    webrtc::VideoSendStream::DegradationPreference GetDegradationPreference()
+        const EXCLUSIVE_LOCKS_REQUIRED(&thread_checker_);
+
     rtc::ThreadChecker thread_checker_;
     rtc::AsyncInvoker invoker_;
     rtc::Thread* worker_thread_;