Move sent key frame stats to send_statistics_proxy class.

webrtc/video_engine/vie_encoder.h

Index: webrtc/video_engine/vie_encoder.h
diff --git a/webrtc/video_engine/vie_encoder.h b/webrtc/video_engine/vie_encoder.h
index 2221f0781debe4225ed0364ff6a2ee31c82d9783..40746f39ba861e50531733e0a1ec7024cf308836 100644
--- a/webrtc/video_engine/vie_encoder.h
+++ b/webrtc/video_engine/vie_encoder.h
@@ -162,8 +162,6 @@ class ViEEncoder : public RtcpIntraFrameObserver,
   void TraceFrameDropStart() EXCLUSIVE_LOCKS_REQUIRED(data_cs_);
   void TraceFrameDropEnd() EXCLUSIVE_LOCKS_REQUIRED(data_cs_);
 
-  void UpdateHistograms();
-
   const int channel_id_;
   const uint32_t number_of_cores_;
 
@@ -206,7 +204,6 @@ class ViEEncoder : public RtcpIntraFrameObserver,
   std::map<uint32_t, int> ssrc_streams_ GUARDED_BY(data_cs_);
 
   bool video_suspended_ GUARDED_BY(data_cs_);
-  const int64_t start_ms_;
 };
 
 }  // namespace webrtc