Request frame for new sinks from MediaStreamVideoTrack

content/renderer/media/media_stream_video_track.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/media_stream_video_track.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/location.h"
@@ skipping 229 matching lines @@
   Stop();
   DVLOG(3) << "~MediaStreamVideoTrack()";
 }
 
 void MediaStreamVideoTrack::AddSink(
     MediaStreamVideoSink* sink, const VideoCaptureDeliverFrameCB& callback) {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   DCHECK(std::find(sinks_.begin(), sinks_.end(), sink) == sinks_.end());
   sinks_.push_back(sink);
   frame_deliverer_->AddCallback(sink, callback);
+  // Request source to deliver a frame because a new sink is added.
+  if (source_)
+    source_->RequestRefreshFrame();
 }
 
 void MediaStreamVideoTrack::RemoveSink(MediaStreamVideoSink* sink) {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   std::vector<MediaStreamVideoSink*>::iterator it =
       std::find(sinks_.begin(), sinks_.end(), sink);
   DCHECK(it != sinks_.end());
   sinks_.erase(it);
   frame_deliverer_->RemoveCallback(sink);
 }
@@ skipping 15 matching lines @@
 }
 
 void MediaStreamVideoTrack::OnReadyStateChanged(
     blink::WebMediaStreamSource::ReadyState state) {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   for (auto* sink : sinks_)
     sink->OnReadyStateChanged(state);
 }
 
 }  // namespace content