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

media/audio/linux/alsa_input.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_LINUX_ALSA_INPUT_H_
 #define MEDIA_AUDIO_LINUX_ALSA_INPUT_H_
 
 #include <alsa/asoundlib.h>
 
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time.h"
+#include "media/audio/audio_input_stream_impl.h"
 #include "media/audio/audio_io.h"
 #include "media/audio/audio_parameters.h"
 
 class AlsaWrapper;
 class AudioManagerLinux;
 
 // Provides an input stream for audio capture based on the ALSA PCM interface.
 // This object is not thread safe and all methods should be invoked in the
 // thread that created the object.
-class AlsaPcmInputStream : public AudioInputStream {
+class AlsaPcmInputStream : public AudioInputStreamImpl {
  public:
   // Pass this to the constructor if you want to attempt auto-selection
   // of the audio recording device.
   static const char* kAutoSelectDevice;
 
   // Create a PCM Output stream for the ALSA device identified by
   // |device_name|. If unsure of what to use for |device_name|, use
   // |kAutoSelectDevice|.
   AlsaPcmInputStream(AudioManagerLinux* audio_manager,
                      const std::string& device_name,
@@ skipping 42 matching lines @@
   snd_mixer_t* mixer_handle_; // Handle to the ALSA microphone mixer.
   snd_mixer_elem_t* mixer_element_handle_; // Handle to the capture element.
   base::WeakPtrFactory<AlsaPcmInputStream> weak_factory_;
   scoped_array<uint8> audio_buffer_;  // Buffer used for reading audio data.
   bool read_callback_behind_schedule_;
 
   DISALLOW_COPY_AND_ASSIGN(AlsaPcmInputStream);
 };
 
 #endif  // MEDIA_AUDIO_LINUX_ALSA_INPUT_H_