Improved AGC update scheme for the audio backend in Chrome

media/audio/mac/audio_low_latency_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.
 //
 // Implementation of AudioInputStream for Mac OS X using the special AUHAL
 // input Audio Unit present in OS 10.4 and later.
 // The AUHAL input Audio Unit is for low-latency audio I/O.
 //
 // Overview of operation:
 //
@@ skipping 24 matching lines @@
 //
 #ifndef MEDIA_AUDIO_MAC_AUDIO_LOW_LATENCY_INPUT_MAC_H_
 #define MEDIA_AUDIO_MAC_AUDIO_LOW_LATENCY_INPUT_MAC_H_
 
 #include <AudioUnit/AudioUnit.h>
 #include <CoreAudio/CoreAudio.h>
 
 #include "base/atomicops.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
+#include "media/audio/agc_audio_stream.h"
 #include "media/audio/audio_io.h"
-#include "media/audio/audio_input_stream_impl.h"
 #include "media/audio/audio_parameters.h"
 #include "media/base/seekable_buffer.h"
 
 namespace media {
 
 class AudioManagerMac;
 class DataBuffer;
 
-class AUAudioInputStream : public AudioInputStreamImpl {
+class AUAudioInputStream : public AgcAudioStream<AudioInputStream> {
  public:
   // The ctor takes all the usual parameters, plus |manager| which is the
   // the audio manager who is creating this object.
   AUAudioInputStream(AudioManagerMac* manager,
                      const AudioParameters& params,
                      AudioDeviceID audio_device_id);
   // The dtor is typically called by the AudioManager only and it is usually
   // triggered by calling AudioInputStream::Close().
   virtual ~AUAudioInputStream();
 
@@ skipping 91 matching lines @@
   // The client requests that the recorded data shall be delivered using
   // OnData() callbacks where each callback contains this amount of bytes.
   int requested_size_bytes_;
 
   DISALLOW_COPY_AND_ASSIGN(AUAudioInputStream);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_MAC_AUDIO_LOW_LATENCY_INPUT_MAC_H_