Add sent framerates to histogram stats:

webrtc/video/send_statistics_proxy.h

Index: webrtc/video/send_statistics_proxy.h
diff --git a/webrtc/video/send_statistics_proxy.h b/webrtc/video/send_statistics_proxy.h
index 4aa74f37a61f2beb8fc416b679833012d6abf513..9f8fd09bd5c39827910d984d0e3524ee6a82158d 100644
--- a/webrtc/video/send_statistics_proxy.h
+++ b/webrtc/video/send_statistics_proxy.h
@@ -98,12 +98,16 @@ class SendStatisticsProxy : public CpuOveruseMetricsObserver,
   void PurgeOldStats() EXCLUSIVE_LOCKS_REQUIRED(crit_);
   VideoSendStream::StreamStats* GetStatsEntry(uint32_t ssrc)
       EXCLUSIVE_LOCKS_REQUIRED(crit_);
+  void UpdateHistograms();
 
   Clock* const clock_;
   const VideoSendStream::Config config_;
   mutable rtc::CriticalSection crit_;
   VideoSendStream::Stats stats_ GUARDED_BY(crit_);
   rtc::RateTracker input_frame_rate_tracker_ GUARDED_BY(crit_);
+  rtc::RateTracker input_frame_rate_tracker_total_ GUARDED_BY(crit_);
+  rtc::RateTracker sent_frame_rate_tracker_total_ GUARDED_BY(crit_);
+  uint32_t last_sent_frame_timestamp_ GUARDED_BY(crit_);
   std::map<uint32_t, StatsUpdateTimes> update_times_ GUARDED_BY(crit_);
 };