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/erl_estimator.h

@@ -0,0 +1,57 @@
+/*
+ *  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_ERL_ESTIMATOR_H_
+#define MODULES_AUDIO_PROCESSING_AEC3_ERL_ESTIMATOR_H_
+
+#include <stddef.h>
+
+#include <array>
+#include <vector>
+
+#include "api/array_view.h"
+#include "modules/audio_processing/aec3/aec3_common.h"
+#include "rtc_base/constructor_magic.h"
+
+namespace webrtc {
+
+// Estimates the echo return loss based on the signal spectra.
+class ErlEstimator {
+ public:
+  explicit ErlEstimator(size_t startup_phase_length_blocks_);
+  ~ErlEstimator();
+
+  // Resets the ERL estimation.
+  void Reset();
+
+  // Updates the ERL estimate.
+  void Update(const std::vector<bool>& converged_filters,
+              rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
+                  render_spectra,
+              rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
+                  capture_spectra);
+
+  // Returns the most recent ERL estimate.
+  const std::array<float, kFftLengthBy2Plus1>& Erl() const { return erl_; }
+  float ErlTimeDomain() const { return erl_time_domain_; }
+
+ private:
+  const size_t startup_phase_length_blocks__;
+  std::array<float, kFftLengthBy2Plus1> erl_;
+  std::array<int, kFftLengthBy2Minus1> hold_counters_;
+  float erl_time_domain_;
+  int hold_counter_time_domain_;
+  size_t blocks_since_reset_ = 0;
+  RTC_DISALLOW_COPY_AND_ASSIGN(ErlEstimator);
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_AUDIO_PROCESSING_AEC3_ERL_ESTIMATOR_H_