Add a reliability term to the echo detector.

webrtc/modules/audio_processing/residual_echo_detector.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 53 matching lines @@
   // Covariance estimates for different delay values.
   std::vector<NormalizedCovarianceEstimator> covariances_;
   // Index where next element should be inserted in all of the above circular
   // buffers.
   size_t next_insertion_index_ = 0;
 
   MeanVarianceEstimator render_statistics_;
   MeanVarianceEstimator capture_statistics_;
   // Current echo likelihood.
   float echo_likelihood_ = 0.f;
+  // Reliability of the current likelihood.
+  float reliability_ = 0.f;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_RESIDUAL_ECHO_DETECTOR_H_