Video Capture: Allow suspension of individual devices.

content/renderer/media/media_stream_video_track.cc

Index: content/renderer/media/media_stream_video_track.cc
diff --git a/content/renderer/media/media_stream_video_track.cc b/content/renderer/media/media_stream_video_track.cc
index e23b290328ddc6aafdea984452fa1336165dd720..2ccdba52d25fd26e6f0d5a386079430a86ce8e71 100644
--- a/content/renderer/media/media_stream_video_track.cc
+++ b/content/renderer/media/media_stream_video_track.cc
@@ -253,6 +253,7 @@ void MediaStreamVideoTrack::AddSink(MediaStreamVideoSink* sink,
   secure_tracker_.Add(sink, is_sink_secure);
   // Request source to deliver a frame because a new sink is added.
   if (source_) {
+    source_->UpdateHasConsumers(this, true);
     source_->RequestRefreshFrame();
     source_->UpdateCapturingLinkSecure(this,
                                        secure_tracker_.is_capturing_secure());
@@ -267,9 +268,12 @@ void MediaStreamVideoTrack::RemoveSink(MediaStreamVideoSink* sink) {
   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) {