Harden audio output controller making it safe to call Pause() before

media/audio/audio_output_controller.h

Index: media/audio/audio_output_controller.h
===================================================================
--- media/audio/audio_output_controller.h	(revision 106670)
+++ media/audio/audio_output_controller.h	(working copy)
@@ -55,16 +55,6 @@
     : public base::RefCountedThreadSafe<AudioOutputController>,
       public AudioOutputStream::AudioSourceCallback {
  public:
-  // Internal state of the source.
-  enum State {
-    kEmpty,
-    kCreated,
-    kPlaying,
-    kPaused,
-    kClosed,
-    kError,
-  };
-
   // Value sent by the controller to the renderer in low-latency mode
   // indicating that the stream is paused.
   static const int kPauseMark;
@@ -169,6 +159,18 @@
                             uint32 max_size, AudioBuffersState buffers_state);
   virtual void OnError(AudioOutputStream* stream, int code);
 
+ protected:
+    // Internal state of the source.
+  enum State {
+    kEmpty,
+    kCreated,
+    kPlaying,
+    kStarting,
+    kPaused,
+    kClosed,
+    kError,
+  };
+
  private:
   // We are polling sync reader if data became available.
   static const int kPollNumAttempts;