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/vad_with_level.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_AGC2_VAD_WITH_LEVEL_H_
+#define MODULES_AUDIO_PROCESSING_AGC2_VAD_WITH_LEVEL_H_
+
+#include <memory>
+
+#include "modules/audio_processing/include/audio_frame_view.h"
+
+namespace webrtc {
+
+// Class to analyze voice activity and audio levels.
+class VadLevelAnalyzer {
+ public:
+  struct Result {
+    float speech_probability;  // Range: [0, 1].
+    float rms_dbfs;            // Root mean square power (dBFS).
+    float peak_dbfs;           // Peak power (dBFS).
+  };
+
+  // Voice Activity Detector (VAD) interface.
+  class VoiceActivityDetector {
+   public:
+    virtual ~VoiceActivityDetector() = default;
+    // Analyzes an audio frame and returns the speech probability.
+    virtual float ComputeProbability(AudioFrameView<const float> frame) = 0;
+  };
+
+  // Ctor. Uses the default VAD.
+  VadLevelAnalyzer();
+  explicit VadLevelAnalyzer(float vad_probability_attack);
+  // Ctor. Uses a custom `vad`.
+  VadLevelAnalyzer(float vad_probability_attack,
+                   std::unique_ptr<VoiceActivityDetector> vad);
+  VadLevelAnalyzer(const VadLevelAnalyzer&) = delete;
+  VadLevelAnalyzer& operator=(const VadLevelAnalyzer&) = delete;
+  ~VadLevelAnalyzer();
+
+  // Computes the speech probability and the level for `frame`.
+  Result AnalyzeFrame(AudioFrameView<const float> frame);
+
+ private:
+  std::unique_ptr<VoiceActivityDetector> vad_;
+  const float vad_probability_attack_;
+  float vad_probability_ = 0.f;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_AUDIO_PROCESSING_AGC2_VAD_WITH_LEVEL_H_