Add content type information to encoded images and corresponding rtp extension header

webrtc/media/base/videobroadcaster.cc

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 48 matching lines @@
       // Calls to OnFrame are not synchronized with changes to the sink wants.
       // When rotation_applied is set to true, one or a few frames may get here
       // with rotation still pending. Protect sinks that don't expect any
       // pending rotation.
       LOG(LS_VERBOSE) << "Discarding frame with unexpected rotation.";
       continue;
     }
     if (sink_pair.wants.black_frames) {
       sink_pair.sink->OnFrame(webrtc::VideoFrame(
           GetBlackFrameBuffer(frame.width(), frame.height()), frame.rotation(),
-          frame.timestamp_us()));
+          frame.content_type(), frame.timestamp_us()));
     } else {
       sink_pair.sink->OnFrame(frame);
     }
   }
 }
 
 void VideoBroadcaster::UpdateWants() {
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
 
   VideoSinkWants wants;
@@ skipping 34 matching lines @@
     rtc::scoped_refptr<webrtc::I420Buffer> buffer =
         webrtc::I420Buffer::Create(width, height);
     webrtc::I420Buffer::SetBlack(buffer.get());
     black_frame_buffer_ = buffer;
   }
 
   return black_frame_buffer_;
 }
 
 }  // namespace rtc