Simplify AudioInputRendererHost IPC interface.

media/audio/audio_input_ipc.h

Index: media/audio/audio_input_ipc.h
diff --git a/media/audio/audio_input_ipc.h b/media/audio/audio_input_ipc.h
index 203449c05a77c65d31e6066712df6561861abaf5..ba1568935bf9739e7fd82bc3846eaf93e5903f99 100644
--- a/media/audio/audio_input_ipc.h
+++ b/media/audio/audio_input_ipc.h
@@ -40,10 +40,7 @@ class MEDIA_EXPORT AudioInputIPCDelegate {
                                int total_segments) = 0;
 
   // Called when state of an audio stream has changed.
-  virtual void OnStateChanged(AudioInputIPCDelegateState state) = 0;
-
-  // Called when the input stream volume has changed.
-  virtual void OnVolume(double volume) = 0;
+  virtual void OnError() = 0;
 
   // Called when the AudioInputIPC object is going away and/or when the
   // IPC channel has been closed and no more IPC requests can be made.