Video Capture: Allow suspension of individual devices.

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 234 matching lines @@
 
 void MediaStreamVideoTrack::AddSink(MediaStreamVideoSink* sink,
                                     const VideoCaptureDeliverFrameCB& callback,
                                     bool is_sink_secure) {
   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);
   secure_tracker_.Add(sink, is_sink_secure);
   // Request source to deliver a frame because a new sink is added.
   if (source_) {

[mcasas, 2016/09/28 21:34:44]

Heh I feel like a scratched record, but, early return?
Here and in l.271.

[miu, 2016/09/28 22:35:15]

Done.

+    source_->UpdateHasConsumers(this, true);
     source_->RequestRefreshFrame();
     source_->UpdateCapturingLinkSecure(this,
                                        secure_tracker_.is_capturing_secure());
   }
 }
 
 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);
   secure_tracker_.Remove(sink);
-  if (source_)
+  if (source_) {
+    if (sinks_.empty())
+      source_->UpdateHasConsumers(this, false);
     source_->UpdateCapturingLinkSecure(this,
                                        secure_tracker_.is_capturing_secure());
+  }
 }
 
 void MediaStreamVideoTrack::SetEnabled(bool enabled) {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   frame_deliverer_->SetEnabled(enabled);
   for (auto* sink : sinks_)
     sink->OnEnabledChanged(enabled);
 }
 
 void MediaStreamVideoTrack::Stop() {
@@ skipping 20 matching lines @@
 }
 
 void MediaStreamVideoTrack::OnReadyStateChanged(
     blink::WebMediaStreamSource::ReadyState state) {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   for (auto* sink : sinks_)
     sink->OnReadyStateChanged(state);
 }
 
 }  // namespace content