Keep track of the capacity delay error in the FakeNetworkPipe.

webrtc/test/fake_network_pipe.h

 /*
  *  Copyright (c) 2012 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 158 matching lines @@
   // burst of packet
   double prob_loss_bursting_;
 
   // The probability to drop a burst of packets.
   double prob_start_bursting_;
 
   int64_t next_process_time_;
 
   int64_t last_log_time_;
 
+  int64_t capacity_delay_error_bytes_ = 0;
+
   RTC_DISALLOW_COPY_AND_ASSIGN(FakeNetworkPipe);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_TEST_FAKE_NETWORK_PIPE_H_