Moved the GainControlForNewAGC class to a separate file.

webrtc/modules/audio_processing/audio_processing_impl.cc

Index: webrtc/modules/audio_processing/audio_processing_impl.cc
diff --git a/webrtc/modules/audio_processing/audio_processing_impl.cc b/webrtc/modules/audio_processing/audio_processing_impl.cc
index 0934b1e4afa9f519fa91e42dde7439f047e009b4..47b28b3f35121f512732548fc6913469a554a3e1 100644
--- a/webrtc/modules/audio_processing/audio_processing_impl.cc
+++ b/webrtc/modules/audio_processing/audio_processing_impl.cc
@@ -29,6 +29,7 @@ extern "C" {
 #include "webrtc/modules/audio_processing/common.h"
 #include "webrtc/modules/audio_processing/echo_cancellation_impl.h"
 #include "webrtc/modules/audio_processing/echo_control_mobile_impl.h"
+#include "webrtc/modules/audio_processing/gain_control_for_new_agc.h"
 #include "webrtc/modules/audio_processing/gain_control_impl.h"
 #include "webrtc/modules/audio_processing/high_pass_filter_impl.h"
 #include "webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.h"
@@ -80,72 +81,6 @@ static bool LayoutHasKeyboard(AudioProcessing::ChannelLayout layout) {
 // Throughout webrtc, it's assumed that success is represented by zero.
 static_assert(AudioProcessing::kNoError == 0, "kNoError must be zero");
 
-// This class has two main functionalities:
-//
-// 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 GainControlForNewAgc : public GainControl, public VolumeCallbacks {
- public:
-  explicit GainControlForNewAgc(GainControlImpl* gain_control)
-      : real_gain_control_(gain_control), volume_(0) {}
-
-  // GainControl implementation.
-  int Enable(bool enable) override {
-    return real_gain_control_->Enable(enable);
-  }
-  bool is_enabled() const override { return real_gain_control_->is_enabled(); }
-  int set_stream_analog_level(int level) override {
-    volume_ = level;
-    return AudioProcessing::kNoError;
-  }
-  int stream_analog_level() override { return volume_; }
-  int set_mode(Mode mode) override { return AudioProcessing::kNoError; }
-  Mode mode() const override { return GainControl::kAdaptiveAnalog; }
-  int set_target_level_dbfs(int level) override {
-    return AudioProcessing::kNoError;
-  }
-  int target_level_dbfs() const override {
-    return real_gain_control_->target_level_dbfs();
-  }
-  int set_compression_gain_db(int gain) override {
-    return AudioProcessing::kNoError;
-  }
-  int compression_gain_db() const override {
-    return real_gain_control_->compression_gain_db();
-  }
-  int enable_limiter(bool enable) override { return AudioProcessing::kNoError; }
-  bool is_limiter_enabled() const override {
-    return real_gain_control_->is_limiter_enabled();
-  }
-  int set_analog_level_limits(int minimum, int maximum) override {
-    return AudioProcessing::kNoError;
-  }
-  int analog_level_minimum() const override {
-    return real_gain_control_->analog_level_minimum();
-  }
-  int analog_level_maximum() const override {
-    return real_gain_control_->analog_level_maximum();
-  }
-  bool stream_is_saturated() const override {
-    return real_gain_control_->stream_is_saturated();
-  }
-
-  // VolumeCallbacks implementation.
-  void SetMicVolume(int volume) override { volume_ = volume; }
-  int GetMicVolume() override { return volume_; }
-
- private:
-  GainControl* real_gain_control_;
-  int volume_;
-};
-
 struct AudioProcessingImpl::ApmPublicSubmodules {
   ApmPublicSubmodules()
       : echo_cancellation(nullptr),