Adding support for handling highly reverberant echoes in AEC3

webrtc/modules/audio_processing/aec3/aec_state.h

 /*
  *  Copyright (c) 2017 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 58 matching lines @@
   void UpdateCaptureSaturation(bool capture_signal_saturation) {
     capture_signal_saturation_ = capture_signal_saturation;
   }
 
   // Returns whether a probable headset setup has been detected.
   bool HeadsetDetected() const { return headset_detected_; }
 
   // Takes appropriate action at an echo path change.
   void HandleEchoPathChange(const EchoPathVariability& echo_path_variability);
 
+  // Returns the decay factor for the echo reverberation.
+  // TODO(peah): Make this adaptive.
+  float ReverbDecayFactor() const { return 0.f; }
+
   // Updates the aec state.
   void Update(const std::vector<std::array<float, kFftLengthBy2Plus1>>&
                   adaptive_filter_frequency_response,
               const rtc::Optional<size_t>& external_delay_samples,
               const RenderBuffer& render_buffer,
               const std::array<float, kFftLengthBy2Plus1>& E2_main,
               const std::array<float, kFftLengthBy2Plus1>& Y2,
               rtc::ArrayView<const float> x,
               bool echo_leakage_detected);
 
@@ skipping 13 matching lines @@
   rtc::Optional<size_t> filter_delay_;
   rtc::Optional<size_t> external_delay_;
   size_t blocks_since_last_saturation_ = 1000;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(AecState);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_AEC_STATE_H_