Decouple c/b/cros/audio from c/b/speech.

chrome/browser/chromeos/audio/audio_mixer.h

Index: chrome/browser/chromeos/audio/audio_mixer.h
diff --git a/chrome/browser/chromeos/audio/audio_mixer.h b/chrome/browser/chromeos/audio/audio_mixer.h
index e31ff2b2fe6805f1189bec9834ef109bd0b7c3f1..77b9ca9f79ad3f0562e4914d4c5148418ad1ac00 100644
--- a/chrome/browser/chromeos/audio/audio_mixer.h
+++ b/chrome/browser/chromeos/audio/audio_mixer.h
@@ -6,6 +6,7 @@
 #define CHROME_BROWSER_CHROMEOS_AUDIO_AUDIO_MIXER_H_
 
 #include "base/basictypes.h"
+#include "base/callback_forward.h"
 
 namespace chromeos {
 
@@ -17,7 +18,7 @@ class AudioMixer {
   // Initializes the connection to the device.  This must be called on the UI
   // thread; blocking tasks may take place in the background.  Note that the
   // other methods in this interface can be called before Init().
-  virtual void Init() = 0;
+  virtual void Init(const base::Closure& on_connected) = 0;
 
   // Returns the most-recently-set volume, in the range [0.0, 100.0].
   virtual double GetVolumePercent() = 0;