Add a placeholder stat for logging the estimated residual echo likelihood.

webrtc/media/base/mediachannel.h

 /*
  *  Copyright (c) 2004 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 569 matching lines @@
 struct VoiceSenderInfo : public MediaSenderInfo {
   VoiceSenderInfo()
       : ext_seqnum(0),
         jitter_ms(0),
         audio_level(0),
         aec_quality_min(0.0),
         echo_delay_median_ms(0),
         echo_delay_std_ms(0),
         echo_return_loss(0),
         echo_return_loss_enhancement(0),
+        residual_echo_likelihood(0.0f),
         typing_noise_detected(false) {
   }
 
   int ext_seqnum;
   int jitter_ms;
   int audio_level;
   float aec_quality_min;
   int echo_delay_median_ms;
   int echo_delay_std_ms;
   int echo_return_loss;
   int echo_return_loss_enhancement;
+  float residual_echo_likelihood;
   bool typing_noise_detected;
 };
 
 struct VoiceReceiverInfo : public MediaReceiverInfo {
   VoiceReceiverInfo()
       : ext_seqnum(0),
         jitter_ms(0),
         jitter_buffer_ms(0),
         jitter_buffer_preferred_ms(0),
         delay_estimate_ms(0),
@@ skipping 521 matching lines @@
   // Signal when the media channel is ready to send the stream. Arguments are:
   //     writable(bool)
   sigslot::signal1<bool> SignalReadyToSend;
   // Signal for notifying that the remote side has closed the DataChannel.
   sigslot::signal1<uint32_t> SignalStreamClosedRemotely;
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_MEDIA_BASE_MEDIACHANNEL_H_