Add plot of network delay change computed based on transport feedback.

webrtc/tools/event_log_visualizer/analyzer.h

 /*
  *  Copyright (c) 2016 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 29 matching lines @@
   void CreateDelayChangeGraph(Plot* plot);
 
   void CreateAccumulatedDelayChangeGraph(Plot* plot);
 
   void CreateTotalBitrateGraph(PacketDirection desired_direction, Plot* plot);
 
   void CreateStreamBitrateGraph(PacketDirection desired_direction, Plot* plot);
 
   void CreateBweGraph(Plot* plot);
 
+  void CreateNetworkDelayFeebackGraph(Plot* plot);
+
  private:
   class StreamId {
    public:
     StreamId(uint32_t ssrc, webrtc::PacketDirection direction)
         : ssrc_(ssrc), direction_(direction) {}
     bool operator<(const StreamId& other) const;
     bool operator==(const StreamId& other) const;
     uint32_t GetSsrc() const { return ssrc_; }
     webrtc::PacketDirection GetDirection() const { return direction_; }
 
@@ skipping 57 matching lines @@
   uint64_t end_time_;
 
   // Duration (in seconds) of log file.
   float call_duration_s_;
 };
 
 }  // namespace plotting
 }  // namespace webrtc
 
 #endif  // WEBRTC_TOOLS_EVENT_LOG_VISUALIZER_ANALYZER_H_