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diff --git a/third_party/libwebrtc/modules/audio_processing/aec3/suppression_gain.h b/third_party/libwebrtc/modules/audio_processing/aec3/suppression_gain.h
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+++ b/third_party/libwebrtc/modules/audio_processing/aec3/suppression_gain.h
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+/*
+ *  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.
+ */
+
+#ifndef MODULES_AUDIO_PROCESSING_AEC3_SUPPRESSION_GAIN_H_
+#define MODULES_AUDIO_PROCESSING_AEC3_SUPPRESSION_GAIN_H_
+
+#include <array>
+#include <atomic>
+#include <memory>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/array_view.h"
+#include "api/audio/echo_canceller3_config.h"
+#include "modules/audio_processing/aec3/aec3_common.h"
+#include "modules/audio_processing/aec3/aec_state.h"
+#include "modules/audio_processing/aec3/fft_data.h"
+#include "modules/audio_processing/aec3/moving_average.h"
+#include "modules/audio_processing/aec3/nearend_detector.h"
+#include "modules/audio_processing/aec3/render_signal_analyzer.h"
+#include "modules/audio_processing/logging/apm_data_dumper.h"
+
+namespace webrtc {
+
+class SuppressionGain {
+ public:
+  SuppressionGain(const EchoCanceller3Config& config,
+                  Aec3Optimization optimization,
+                  int sample_rate_hz,
+                  size_t num_capture_channels);
+  ~SuppressionGain();
+
+  SuppressionGain(const SuppressionGain&) = delete;
+  SuppressionGain& operator=(const SuppressionGain&) = delete;
+
+  void GetGain(
+      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
+          nearend_spectrum,
+      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> echo_spectrum,
+      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
+          residual_echo_spectrum,
+      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
+          residual_echo_spectrum_unbounded,
+      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
+          comfort_noise_spectrum,
+      const RenderSignalAnalyzer& render_signal_analyzer,
+      const AecState& aec_state,
+      const Block& render,
+      bool clock_drift,
+      float* high_bands_gain,
+      std::array<float, kFftLengthBy2Plus1>* low_band_gain);
+
+  bool IsDominantNearend() {
+    return dominant_nearend_detector_->IsNearendState();
+  }
+
+  // Toggles the usage of the initial state.
+  void SetInitialState(bool state);
+
+ private:
+  // Computes the gain to apply for the bands beyond the first band.
+  float UpperBandsGain(
+      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> echo_spectrum,
+      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
+          comfort_noise_spectrum,
+      const absl::optional<int>& narrow_peak_band,
+      bool saturated_echo,
+      const Block& render,
+      const std::array<float, kFftLengthBy2Plus1>& low_band_gain) const;
+
+  void GainToNoAudibleEcho(const std::array<float, kFftLengthBy2Plus1>& nearend,
+                           const std::array<float, kFftLengthBy2Plus1>& echo,
+                           const std::array<float, kFftLengthBy2Plus1>& masker,
+                           std::array<float, kFftLengthBy2Plus1>* gain) const;
+
+  void LowerBandGain(
+      bool stationary_with_low_power,
+      const AecState& aec_state,
+      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
+          suppressor_input,
+      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> residual_echo,
+      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> comfort_noise,
+      bool clock_drift,
+      std::array<float, kFftLengthBy2Plus1>* gain);
+
+  void GetMinGain(rtc::ArrayView<const float> weighted_residual_echo,
+                  rtc::ArrayView<const float> last_nearend,
+                  rtc::ArrayView<const float> last_echo,
+                  bool low_noise_render,
+                  bool saturated_echo,
+                  rtc::ArrayView<float> min_gain) const;
+
+  void GetMaxGain(rtc::ArrayView<float> max_gain) const;
+
+  class LowNoiseRenderDetector {
+   public:
+    bool Detect(const Block& render);
+
+   private:
+    float average_power_ = 32768.f * 32768.f;
+  };
+
+  struct GainParameters {
+    explicit GainParameters(
+        int last_lf_band,
+        int first_hf_band,
+        const EchoCanceller3Config::Suppressor::Tuning& tuning);
+    const float max_inc_factor;
+    const float max_dec_factor_lf;
+    std::array<float, kFftLengthBy2Plus1> enr_transparent_;
+    std::array<float, kFftLengthBy2Plus1> enr_suppress_;
+    std::array<float, kFftLengthBy2Plus1> emr_transparent_;
+  };
+
+  static std::atomic<int> instance_count_;
+  std::unique_ptr<ApmDataDumper> data_dumper_;
+  const Aec3Optimization optimization_;
+  const EchoCanceller3Config config_;
+  const size_t num_capture_channels_;
+  const int state_change_duration_blocks_;
+  std::array<float, kFftLengthBy2Plus1> last_gain_;
+  std::vector<std::array<float, kFftLengthBy2Plus1>> last_nearend_;
+  std::vector<std::array<float, kFftLengthBy2Plus1>> last_echo_;
+  LowNoiseRenderDetector low_render_detector_;
+  bool initial_state_ = true;
+  int initial_state_change_counter_ = 0;
+  std::vector<aec3::MovingAverage> nearend_smoothers_;
+  const GainParameters nearend_params_;
+  const GainParameters normal_params_;
+  // Determines if the dominant nearend detector uses the unbounded residual
+  // echo spectrum.
+  const bool use_unbounded_echo_spectrum_;
+  std::unique_ptr<NearendDetector> dominant_nearend_detector_;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_AUDIO_PROCESSING_AEC3_SUPPRESSION_GAIN_H_