Removing some old code which looked like it had to do with NACK handling but in reality did nothing.

webrtc/voice_engine/channel.cc

 /*
  *  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 2896 matching lines @@
 bool Channel::GetCodecFECStatus() {
   return codec_manager_.GetStackParams()->use_codec_fec;
 }
 
 void Channel::SetNACKStatus(bool enable, int maxNumberOfPackets) {
   // None of these functions can fail.
   // If pacing is enabled we always store packets.
   if (!pacing_enabled_)
     _rtpRtcpModule->SetStorePacketsStatus(enable, maxNumberOfPackets);
   rtp_receive_statistics_->SetMaxReorderingThreshold(maxNumberOfPackets);
-  rtp_receiver_->SetNACKStatus(enable ? kNackRtcp : kNackOff);
   if (enable)
     audio_coding_->EnableNack(maxNumberOfPackets);
   else
     audio_coding_->DisableNack();
 }
 
 // Called when we are missing one or more packets.
 int Channel::ResendPackets(const uint16_t* sequence_numbers, int length) {
   return _rtpRtcpModule->SendNACK(sequence_numbers, length);
 }
@@ skipping 618 matching lines @@
   int64_t min_rtt = 0;
   if (_rtpRtcpModule->RTT(remoteSSRC, &rtt, &avg_rtt, &min_rtt, &max_rtt) !=
       0) {
     return 0;
   }
   return rtt;
 }
 
 }  // namespace voe
 }  // namespace webrtc