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

media/audio/linux/alsa_input.h

Index: media/audio/linux/alsa_input.h
diff --git a/media/audio/linux/alsa_input.h b/media/audio/linux/alsa_input.h
index bbe965de030d0063fc2f1cdec02b3fdc18f93e10..6f6a981356e0eae96205d42e965db51bc66beaff 100644
--- a/media/audio/linux/alsa_input.h
+++ b/media/audio/linux/alsa_input.h
@@ -13,6 +13,7 @@
 #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"
 
@@ -22,7 +23,7 @@ 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.