Update to current webrtc library

This is from the upstream library commit id
3326535126e435f1ba647885ce43a8f0f3d317eb, corresponding to Chromium
88.0.4290.1.

webrtc/modules/audio_processing/aec3/reverb_model.h

@@ -0,0 +1,58 @@
+/*
+ *  Copyright (c) 2018 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.
+ */
+
+#ifndef MODULES_AUDIO_PROCESSING_AEC3_REVERB_MODEL_H_
+#define MODULES_AUDIO_PROCESSING_AEC3_REVERB_MODEL_H_
+
+#include <array>
+
+#include "api/array_view.h"
+#include "modules/audio_processing/aec3/aec3_common.h"
+
+namespace webrtc {
+
+// The ReverbModel class describes an exponential reverberant model
+// that can be applied over power spectrums.
+class ReverbModel {
+ public:
+  ReverbModel();
+  ~ReverbModel();
+
+  // Resets the state.
+  void Reset();
+
+  // Returns the reverb.
+  rtc::ArrayView<const float, kFftLengthBy2Plus1> reverb() const {
+    return reverb_;
+  }
+
+  // The methods UpdateReverbNoFreqShaping and UpdateReverb update the
+  // estimate of the reverberation contribution to an input/output power
+  // spectrum. Before applying the exponential reverberant model, the input
+  // power spectrum is pre-scaled. Use the method UpdateReverb when a different
+  // scaling should be applied per frequency and UpdateReverb_no_freq_shape if
+  // the same scaling should be used for all the frequencies.
+  void UpdateReverbNoFreqShaping(rtc::ArrayView<const float> power_spectrum,
+                                 float power_spectrum_scaling,
+                                 float reverb_decay);
+
+  // Update the reverb based on new data.
+  void UpdateReverb(rtc::ArrayView<const float> power_spectrum,
+                    rtc::ArrayView<const float> power_spectrum_scaling,
+                    float reverb_decay);
+
+ private:
+
+  std::array<float, kFftLengthBy2Plus1> reverb_;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_AUDIO_PROCESSING_AEC3_REVERB_MODEL_H_