Spec compliant video constraints for getUserMedia behind flag.

content/public/renderer/media_stream_utils.cc

Index: content/public/renderer/media_stream_utils.cc
diff --git a/content/public/renderer/media_stream_utils.cc b/content/public/renderer/media_stream_utils.cc
index 114728646c4be8a38c5ac32fa20d1bac19924bcd..26cd9d2b8977df95786ebfb4a37b881165284d2a 100644
--- a/content/public/renderer/media_stream_utils.cc
+++ b/content/public/renderer/media_stream_utils.cc
@@ -44,12 +44,9 @@ bool AddVideoTrackToMediaStream(
       track_id, blink::WebMediaStreamSource::TypeVideo, track_id, is_remote);
   // Takes ownership of |media_stream_source|.
   web_media_stream_source.setExtraData(media_stream_source);
-
-  blink::WebMediaConstraints constraints;
-  constraints.initialize();
   web_media_stream->addTrack(MediaStreamVideoTrack::CreateVideoTrack(
-      media_stream_source, constraints,
-      MediaStreamVideoSource::ConstraintsCallback(), true));
+      media_stream_source, MediaStreamVideoSource::ConstraintsCallback(),
+      true));
   return true;
 }