Add average rtt to CallStatsObserver and an average rtt histogram.

webrtc/modules/remote_bitrate_estimator/test/estimators/remb.cc

 /*
  *  Copyright (c) 2015 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 59 matching lines @@
       latest_estimate_bps_(-1),
       last_feedback_ms_(-1),
       estimator_(new RemoteBitrateEstimatorAbsSendTime(
           this,
           &clock_,
           kRemoteBitrateEstimatorMinBitrateBps)) {
   std::stringstream ss;
   ss << "Estimate_" << flow_id_ << "#1";
   estimate_log_prefix_ = ss.str();
   // Default RTT in RemoteRateControl is 200 ms ; 50 ms is more realistic.
-  estimator_->OnRttUpdate(50);
+  estimator_->OnRttUpdate(50, 50);
 }
 
 RembReceiver::~RembReceiver() {
 }
 
 void RembReceiver::ReceivePacket(int64_t arrival_time_ms,
                                  const MediaPacket& media_packet) {
   recv_stats_->IncomingPacket(media_packet.header(),
                               media_packet.payload_size(), false);
 
@@ skipping 66 matching lines @@
     }
     latest_estimate_bps_ = bps;
   }
   *estimate_bps = latest_estimate_bps_;
   return true;
 }
 
 }  // namespace bwe
 }  // namespace testing
 }  // namespace webrtc