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 71159f6604d93faeefaa5c999a989d7539232143..91a7d1c6c4819564110a3f309a32a34bc96bb215 100644
--- a/content/public/renderer/media_stream_utils.cc
+++ b/content/public/renderer/media_stream_utils.cc
@@ -43,12 +43,9 @@ 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;
 }