Implement framesEncoded stat in video send ssrc stats.

webrtc/api/statscollector.cc

Index: webrtc/api/statscollector.cc
diff --git a/webrtc/api/statscollector.cc b/webrtc/api/statscollector.cc
index 766e94980384ceb32d91130edd2e2ee651b3f2e2..aed6b3f4d8b2977c80571d7e01cdd2d33ac6cd5e 100644
--- a/webrtc/api/statscollector.cc
+++ b/webrtc/api/statscollector.cc
@@ -261,6 +261,7 @@ void ExtractStats(const cricket::VideoSenderInfo& info, StatsReport* report) {
     { StatsReport::kStatsValueNamePacketsLost, info.packets_lost },
     { StatsReport::kStatsValueNamePacketsSent, info.packets_sent },
     { StatsReport::kStatsValueNamePlisReceived, info.plis_rcvd },
+    { StatsReport::kStatsValueNameFramesEncoded, info.frames_encoded },
   };
 
   for (const auto& i : ints)