Remove unused RenderIO() interface.

media/audio/audio_output_device.h

Index: media/audio/audio_output_device.h
diff --git a/media/audio/audio_output_device.h b/media/audio/audio_output_device.h
index 0b54b9ae8142d9f66aed97dfa85bb1ec1813c51f..8449e9faa14739cbe5ef961c9633f76e7f1187a6 100644
--- a/media/audio/audio_output_device.h
+++ b/media/audio/audio_output_device.h
@@ -86,10 +86,7 @@ class MEDIA_EXPORT AudioOutputDevice
   // number of input channels which will be at the same sample-rate
   // and buffer-size as the output as specified in |params|. |session_id| is
   // used for the browser to select the correct input device.
-  // In this case, the callback's RenderIO() method will be called instead
-  // of Render(), providing the synchronized input data at the same time as
-  // when new output data is to be rendered.
-  void InitializeUnifiedStream(const AudioParameters& params,
+  void InitializeWithSessionId(const AudioParameters& params,
                                RenderCallback* callback,
                                int session_id);