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..e69f33d4c8584cd129e91808b5e5d0a0ddd06be9 100644
--- a/media/audio/audio_input_ipc.h
+++ b/media/audio/audio_input_ipc.h
@@ -14,13 +14,6 @@
 
 namespace media {
 
-enum AudioInputIPCDelegateState {
-  AUDIO_INPUT_IPC_DELEGATE_STATE_RECORDING,
-  AUDIO_INPUT_IPC_DELEGATE_STATE_STOPPED,
-  AUDIO_INPUT_IPC_DELEGATE_STATE_ERROR,
-  AUDIO_INPUT_IPC_DELEGATE_STATE_LAST = AUDIO_INPUT_IPC_DELEGATE_STATE_ERROR,
-};
-
 // Contains IPC notifications for the state of the server side
 // (AudioInputController) audio state changes and when an AudioInputController
 // has been created.  Implemented by AudioInputDevice.
@@ -40,10 +33,7 @@ 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.