Remove unused flush operation from Chromium audio.

media/audio/audio_output_controller.h

Index: media/audio/audio_output_controller.h
diff --git a/media/audio/audio_output_controller.h b/media/audio/audio_output_controller.h
index 3f158a59b5c4a23c5b6afe4eaf45a0f42678f9b2..0a83bae054c7c2ad3b52303454ed32d32a1119bc 100644
--- a/media/audio/audio_output_controller.h
+++ b/media/audio/audio_output_controller.h
@@ -122,10 +122,6 @@ class MEDIA_EXPORT AudioOutputController
   // Pause this audio output stream.
   void Pause();
 
-  // Discard all audio data buffered in this output stream. This method only
-  // has effect when the stream is paused.
-  void Flush();
-
   // Closes the audio output stream. The state is changed and the resources
   // are freed on the audio manager thread. closed_task is executed after that.
   // Callbacks (EventHandler and SyncReader) must exist until closed_task is
@@ -188,7 +184,6 @@ class MEDIA_EXPORT AudioOutputController
   void DoPlay();
   void PollAndStartIfDataReady();
   void DoPause();
-  void DoFlush();
   void DoClose();
   void DoSetVolume(double volume);
   void DoReportError();