Add MediaStreamSource frame rate calculation to the tracker.

content/renderer/media/peer_connection_tracker.cc

Index: content/renderer/media/peer_connection_tracker.cc
diff --git a/content/renderer/media/peer_connection_tracker.cc b/content/renderer/media/peer_connection_tracker.cc
index 8e368b4e564cf9283cb6792af8fb30b6f5a75d03..66f7ebf9807a3ed55bde7f040713af40c3a3914a 100644
--- a/content/renderer/media/peer_connection_tracker.cc
+++ b/content/renderer/media/peer_connection_tracker.cc
@@ -527,6 +527,13 @@ void PeerConnectionTracker::TrackGetUserMedia(
       SerializeMediaConstraints(video_constraints)));
 }
 
+void PeerConnectionTracker::TrackAddVideoStats(const std::string& video_id,
+                                               float input_frame_rate,
+                                               int number_of_dropped_frames) {
+  RenderThreadImpl::current()->Send(new PeerConnectionTrackerHost_AddVideoStats(
+      video_id, input_frame_rate, number_of_dropped_frames));
+}
+
 int PeerConnectionTracker::GetNextLocalID() {
   return next_lid_++;
 }