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

content/renderer/media/audio_input_device.h

Index: content/renderer/media/audio_input_device.h
diff --git a/content/renderer/media/audio_input_device.h b/content/renderer/media/audio_input_device.h
index ed855548fbaa3dea40fad0eceda59c633ea51f89..4bff6dca3654fe21573041c1e92602ad0f2f6f40 100644
--- a/content/renderer/media/audio_input_device.h
+++ b/content/renderer/media/audio_input_device.h
@@ -95,7 +95,8 @@ class CONTENT_EXPORT AudioInputDevice
    public:
     virtual void Capture(const std::vector<float*>& audio_data,
                          size_t number_of_frames,
-                         size_t audio_delay_milliseconds) = 0;
+                         size_t audio_delay_milliseconds,
+                         double volume) = 0;
     virtual void OnCaptureError() = 0;
    protected:
     virtual ~CaptureCallback() {}
@@ -144,6 +145,10 @@ class CONTENT_EXPORT AudioInputDevice
   // Returns |true| on success.
   bool GetVolume(double* volume);
 
+  // Sets the Automatic Gain Control state to on or off.
+  // TODO(henrika): extend the comments here...

[tommi (sloooow) - chröme, 2012/03/16 13:31:05]

ping (or just remove the todo)

[scherkus (not reviewing), 2012/03/20 13:49:41]

ping again! :P

[henrika (OOO until Aug 14), 2012/03/21 10:16:04]

Much better now ;-)

+  void SetAutomaticGainControl(bool enabled);
+
   double sample_rate() const { return audio_parameters_.sample_rate; }
   size_t buffer_size() const { return audio_parameters_.samples_per_packet; }
 
@@ -166,6 +171,7 @@ class CONTENT_EXPORT AudioInputDevice
   void StartOnIOThread();
   void ShutDownOnIOThread();
   void SetVolumeOnIOThread(double volume);
+  void SetAutomaticGainControlOnIOThread(bool enabled);
 
   void Send(IPC::Message* message);
 
@@ -196,6 +202,10 @@ class CONTENT_EXPORT AudioInputDevice
   // callback. Only modified on the IO thread.
   bool pending_device_ready_;
 
+  // Stores the Automatic Gain Control state. Default is false.
+  // Only modified on the IO thread.
+  bool agc_is_enabled_;
+
   // Our audio thread callback class.  See source file for details.
   class AudioThreadCallback;