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/agc2/rnn_vad/pitch_search.cc

@@ -0,0 +1,56 @@
+/*
+ *  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.
+ */
+
+#include "modules/audio_processing/agc2/rnn_vad/pitch_search.h"
+
+#include <array>
+#include <cstddef>
+
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+namespace rnn_vad {
+
+PitchEstimator::PitchEstimator()
+    : pitch_buf_decimated_(kBufSize12kHz),
+      pitch_buf_decimated_view_(pitch_buf_decimated_.data(), kBufSize12kHz),
+      auto_corr_(kNumInvertedLags12kHz),
+      auto_corr_view_(auto_corr_.data(), kNumInvertedLags12kHz) {
+  RTC_DCHECK_EQ(kBufSize12kHz, pitch_buf_decimated_.size());
+  RTC_DCHECK_EQ(kNumInvertedLags12kHz, auto_corr_view_.size());
+}
+
+PitchEstimator::~PitchEstimator() = default;
+
+PitchInfo PitchEstimator::Estimate(
+    rtc::ArrayView<const float, kBufSize24kHz> pitch_buf) {
+  // Perform the initial pitch search at 12 kHz.
+  Decimate2x(pitch_buf, pitch_buf_decimated_view_);
+  auto_corr_calculator_.ComputeOnPitchBuffer(pitch_buf_decimated_view_,
+                                             auto_corr_view_);
+  std::array<size_t, 2> pitch_candidates_inv_lags = FindBestPitchPeriods(
+      auto_corr_view_, pitch_buf_decimated_view_, kMaxPitch12kHz);
+  // Refine the pitch period estimation.
+  // The refinement is done using the pitch buffer that contains 24 kHz samples.
+  // Therefore, adapt the inverted lags in |pitch_candidates_inv_lags| from 12
+  // to 24 kHz.
+  pitch_candidates_inv_lags[0] *= 2;
+  pitch_candidates_inv_lags[1] *= 2;
+  size_t pitch_inv_lag_48kHz =
+      RefinePitchPeriod48kHz(pitch_buf, pitch_candidates_inv_lags);
+  // Look for stronger harmonics to find the final pitch period and its gain.
+  RTC_DCHECK_LT(pitch_inv_lag_48kHz, kMaxPitch48kHz);
+  last_pitch_48kHz_ = CheckLowerPitchPeriodsAndComputePitchGain(
+      pitch_buf, kMaxPitch48kHz - pitch_inv_lag_48kHz, last_pitch_48kHz_);
+  return last_pitch_48kHz_;
+}
+
+}  // namespace rnn_vad
+}  // namespace webrtc