Adding microphone volume support to chrome.

media/audio/audio_io.h

Index: media/audio/audio_io.h
diff --git a/media/audio/audio_io.h b/media/audio/audio_io.h
index 173f4f54363b65903b86baab30ecb9f0b5a29f58..00a7c7a46ab0012ca61daff3e91b7ec95ff69ace 100644
--- a/media/audio/audio_io.h
+++ b/media/audio/audio_io.h
@@ -154,6 +154,16 @@ class MEDIA_EXPORT AudioInputStream {
   // Close the stream. This also generates AudioInputCallback::OnClose(). This
   // should be the last call made on this object.
   virtual void Close() = 0;
+
+  // Returns the maximum microphone analog volume or 0.0 if device does not
+  // have volume control.
+  virtual double GetMaxVolume() = 0;
+
+  // Sets the microphone analog volume, with range [0, max_volume] inclusive.
+  virtual void SetVolume(double volume) = 0;
+
+  // Returns the microphone analog volume, with range [0, max_volume] inclusive.
+  virtual double GetVolume() = 0;
 };
 
 #endif  // MEDIA_AUDIO_AUDIO_IO_H_