Adds Analog Gain Control (AGC) to the WebRTC client.

media/audio/mac/audio_input_mac.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_AUDIO_MAC_AUDIO_INPUT_MAC_H_
 #define MEDIA_AUDIO_MAC_AUDIO_INPUT_MAC_H_
 
 #include <AudioToolbox/AudioQueue.h>
 #include <AudioToolbox/AudioFormat.h>
 
@@ skipping 13 matching lines @@
   virtual ~PCMQueueInAudioInputStream();
 
   // Implementation of AudioInputStream.
   virtual bool Open() OVERRIDE;
   virtual void Start(AudioInputCallback* callback) OVERRIDE;
   virtual void Stop() OVERRIDE;
   virtual void Close() OVERRIDE;
   virtual double GetMaxVolume() OVERRIDE;
   virtual void SetVolume(double volume) OVERRIDE;
   virtual double GetVolume() OVERRIDE;
+  virtual void SetAutomaticGainControl(bool enabled) OVERRIDE;
+  virtual bool GetAutomaticGainControl() OVERRIDE;
 
  private:
   // Issue the OnError to |callback_|;
   void HandleError(OSStatus err);
 
   // Allocates and prepares the memory that will be used for recording.
   bool SetupBuffers();
 
   // Sends a buffer to the audio driver for recording.
   OSStatus QueueNextBuffer(AudioQueueBufferRef audio_buffer);
@@ skipping 26 matching lines @@
   AudioQueueRef audio_queue_;
   // Size of each of the buffers in |audio_buffers_|
   uint32 buffer_size_bytes_;
   // True iff Start() has been called successfully.
   bool started_;
 
   DISALLOW_COPY_AND_ASSIGN(PCMQueueInAudioInputStream);
 };
 
 #endif  // MEDIA_AUDIO_MAC_AUDIO_INPUT_MAC_H_