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..cdfa86fb1defc60a53762f508c99387066dc27bc 100644
--- a/content/renderer/media/media_stream_video_track.cc
+++ b/content/renderer/media/media_stream_video_track.cc
@@ -252,11 +252,12 @@ void MediaStreamVideoTrack::AddSink(MediaStreamVideoSink* 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_) {
-    source_->RequestRefreshFrame();
-    source_->UpdateCapturingLinkSecure(this,
-                                       secure_tracker_.is_capturing_secure());
-  }
+  if (!source_)
+    return;
+  source_->UpdateHasConsumers(this, true);
+  source_->RequestRefreshFrame();
+  source_->UpdateCapturingLinkSecure(this,
+                                     secure_tracker_.is_capturing_secure());
 }
 
 void MediaStreamVideoTrack::RemoveSink(MediaStreamVideoSink* sink) {
@@ -267,9 +268,12 @@ void MediaStreamVideoTrack::RemoveSink(MediaStreamVideoSink* sink) {
   sinks_.erase(it);
   frame_deliverer_->RemoveCallback(sink);
   secure_tracker_.Remove(sink);
-  if (source_)
-    source_->UpdateCapturingLinkSecure(this,
-                                       secure_tracker_.is_capturing_secure());
+  if (!source_)
+    return;
+  if (sinks_.empty())
+    source_->UpdateHasConsumers(this, false);
+  source_->UpdateCapturingLinkSecure(this,
+                                     secure_tracker_.is_capturing_secure());
 }
 
 void MediaStreamVideoTrack::SetEnabled(bool enabled) {