Adding support for handling highly reverberant echoes in AEC3

webrtc/modules/audio_processing/aec3/aec_state.h

Index: webrtc/modules/audio_processing/aec3/aec_state.h
diff --git a/webrtc/modules/audio_processing/aec3/aec_state.h b/webrtc/modules/audio_processing/aec3/aec_state.h
index 7905be051323dd14d880eec645fc2392a20e16a5..00b62529f64e5724b0c74deeca23f0fa6316485b 100644
--- a/webrtc/modules/audio_processing/aec3/aec_state.h
+++ b/webrtc/modules/audio_processing/aec3/aec_state.h
@@ -76,6 +76,10 @@ class AecState {
   // 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,