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/agc/mock_agc.h

@@ -0,0 +1,34 @@
+/*
+ *  Copyright (c) 2012 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_AGC_MOCK_AGC_H_
+#define MODULES_AUDIO_PROCESSING_AGC_MOCK_AGC_H_
+
+#include "modules/audio_processing/agc/agc.h"
+#include "test/gmock.h"
+
+namespace webrtc {
+
+class MockAgc : public Agc {
+ public:
+  virtual ~MockAgc() {}
+  MOCK_METHOD(void,
+              Process,
+              (const int16_t* audio, size_t length, int sample_rate_hz),
+              (override));
+  MOCK_METHOD(bool, GetRmsErrorDb, (int* error), (override));
+  MOCK_METHOD(void, Reset, (), (override));
+  MOCK_METHOD(int, set_target_level_dbfs, (int level), (override));
+  MOCK_METHOD(int, target_level_dbfs, (), (const, override));
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_AUDIO_PROCESSING_AGC_MOCK_AGC_H_