RTCMediaStreamTrackStats.framesSent collected by RTCStatsCollector.

webrtc/api/rtcstatscollector.cc

Index: webrtc/api/rtcstatscollector.cc
diff --git a/webrtc/api/rtcstatscollector.cc b/webrtc/api/rtcstatscollector.cc
index 5d782736a37f62604f9013569ed68e4a447fa984..27afcc14ecac8ec6dd599356765038a53e3787ad 100644
--- a/webrtc/api/rtcstatscollector.cc
+++ b/webrtc/api/rtcstatscollector.cc
@@ -410,6 +410,9 @@ ProduceMediaStreamTrackStatsFromVideoSenderInfo(
       video_sender_info.send_frame_width);
   video_track_stats->frame_height = static_cast<uint32_t>(
       video_sender_info.send_frame_height);
+  // TODO(hbos): Will reduce this by frames dropped due to congestion control
+  // when available. crbug.com/659137
+  video_track_stats->frames_sent = video_sender_info.frames_encoded;
   return video_track_stats;
 }