Add histogram stats for jitter buffer delay and target delay for received video streams:

webrtc/video/receive_statistics_proxy.h

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 90 matching lines @@
   rtc::CriticalSection crit_;
   VideoReceiveStream::Stats stats_ GUARDED_BY(crit_);
   RateStatistics decode_fps_estimator_ GUARDED_BY(crit_);
   RateStatistics renders_fps_estimator_ GUARDED_BY(crit_);
   rtc::RateTracker render_fps_tracker_ GUARDED_BY(crit_);
   rtc::RateTracker render_pixel_tracker_ GUARDED_BY(crit_);
   SampleCounter render_width_counter_ GUARDED_BY(crit_);
   SampleCounter render_height_counter_ GUARDED_BY(crit_);
   SampleCounter sync_offset_counter_ GUARDED_BY(crit_);
   SampleCounter decode_time_counter_ GUARDED_BY(crit_);
+  SampleCounter jitter_buffer_delay_counter_ GUARDED_BY(crit_);
+  SampleCounter target_delay_counter_ GUARDED_BY(crit_);
   SampleCounter delay_counter_ GUARDED_BY(crit_);
   ReportBlockStats report_block_stats_ GUARDED_BY(crit_);
   QpCounters qp_counters_;  // Only accessed on the decoding thread.
   std::map<uint32_t, StreamDataCounters> rtx_stats_ GUARDED_BY(crit_);
 };
 
 }  // namespace webrtc
 #endif  // WEBRTC_VIDEO_RECEIVE_STATISTICS_PROXY_H_