Propagate MediaStreamTrack video content hints.

content/renderer/media/webrtc/media_stream_video_webrtc_sink.h

Index: content/renderer/media/webrtc/media_stream_video_webrtc_sink.h
diff --git a/content/renderer/media/webrtc/media_stream_video_webrtc_sink.h b/content/renderer/media/webrtc/media_stream_video_webrtc_sink.h
index d881405b52232c62743b261fbd8945ab79049e20..f7d6f37bf7ea090079d9f0fe59961dad75b41687 100644
--- a/content/renderer/media/webrtc/media_stream_video_webrtc_sink.h
+++ b/content/renderer/media/webrtc/media_stream_video_webrtc_sink.h
@@ -42,6 +42,8 @@ class CONTENT_EXPORT MediaStreamVideoWebRtcSink : public MediaStreamVideoSink {
  protected:
   // Implementation of MediaStreamSink.
   void OnEnabledChanged(bool enabled) override;
+  void OnContentHintChanged(
+      blink::WebMediaStreamTrack::ContentHintType content_hint) override;
 
  private:
   // Helper to request a refresh frame from the source. Called via the callback