Moved the GainControlForNewAGC class to a separate file.

webrtc/modules/audio_processing/gain_control_for_experimental_agc.h

+/*
+ *  Copyright (c) 2016 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 WEBRTC_MODULES_AUDIO_PROCESSING_GAIN_CONTROL_FOR_EXPERIMENTAL_AGC_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_GAIN_CONTROL_FOR_EXPERIMENTAL_AGC_H_
+
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/base/thread_checker.h"
+#include "webrtc/modules/audio_processing/agc/agc_manager_direct.h"
+#include "webrtc/modules/audio_processing/include/audio_processing.h"
+
+namespace webrtc {
+
+// This class has two main purposes:
+//
+// 1) It is returned instead of the real GainControl after the new AGC has been
+//    enabled in order to prevent an outside user from overriding compression
+//    settings. It doesn't do anything in its implementation, except for
+//    delegating the const methods and Enable calls to the real GainControl, so
+//    AGC can still be disabled.
+//
+// 2) It is injected into AgcManagerDirect and implements volume callbacks for
+//    getting and setting the volume level. It just caches this value to be used
+//    in VoiceEngine later.
+class GainControlForExperimentalAgc : public GainControl,
+                                      public VolumeCallbacks {
+ public:
+  explicit GainControlForExperimentalAgc(GainControl* gain_control);
+
+  // GainControl implementation.
+  int Enable(bool enable) override;
+  bool is_enabled() const override;
+  int set_stream_analog_level(int level) override;
+  int stream_analog_level() override;
+  int set_mode(Mode mode) override;
+  Mode mode() const override;
+  int set_target_level_dbfs(int level) override;
+  int target_level_dbfs() const override;
+  int set_compression_gain_db(int gain) override;
+  int compression_gain_db() const override;
+  int enable_limiter(bool enable) override;
+  bool is_limiter_enabled() const override;
+  int set_analog_level_limits(int minimum, int maximum) override;
+  int analog_level_minimum() const override;
+  int analog_level_maximum() const override;
+  bool stream_is_saturated() const override;
+
+  // VolumeCallbacks implementation.
+  void SetMicVolume(int volume) override;
+  int GetMicVolume() override;
+
+ private:
+  GainControl* real_gain_control_;
+  int volume_;
+  rtc::ThreadChecker thread_checker;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(GainControlForExperimentalAgc);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_GAIN_CONTROL_FOR_EXPERIMENTAL_AGC_H_