Factor out AudioOutputDelegate from AudioRendererHost.

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 856716f7774f943f9342b1c951d53eef6fce6091..de4bb0fe5ed33051349e42db25a399f138f20acf 100644
--- a/media/audio/audio_output_controller.h
+++ b/media/audio/audio_output_controller.h
@@ -71,10 +71,10 @@ class MEDIA_EXPORT AudioOutputController
   // following methods are called on the audio manager thread.
   class MEDIA_EXPORT EventHandler {
    public:
-    virtual void OnCreated() = 0;
-    virtual void OnPlaying() = 0;
-    virtual void OnPaused() = 0;
-    virtual void OnError() = 0;
+    virtual void OnControllerCreated() = 0;
+    virtual void OnControllerPlaying() = 0;
+    virtual void OnControllerPaused() = 0;
+    virtual void OnControllerError() = 0;
 
    protected:
     virtual ~EventHandler() {}
@@ -108,14 +108,16 @@ class MEDIA_EXPORT AudioOutputController
   // Factory method for creating an AudioOutputController.
   // This also creates and opens an AudioOutputStream on the audio manager
   // thread, and if this is successful, the |event_handler| will receive an
-  // OnCreated() call from the same audio manager thread.  |audio_manager| must
-  // outlive AudioOutputController.
+  // OnControllerCreated() call from the same audio manager thread.
+  // |audio_manager| must outlive AudioOutputController.
   // The |output_device_id| can be either empty (default device) or specify a
   // specific hardware device for audio output.
   static scoped_refptr<AudioOutputController> Create(
-      AudioManager* audio_manager, EventHandler* event_handler,
-      const AudioParameters& params, const std::string& output_device_id,
-      SyncReader* sync_reader);
+      AudioManager* audio_manager,
+      EventHandler* event_handler,
+      const AudioParameters& params,
+      const std::string& output_device_id,
+      std::unique_ptr<SyncReader> sync_reader);
 
   // Indicates whether audio power level analysis will be performed.  If false,
   // ReadCurrentPowerAndClip() can not be called.
@@ -188,6 +190,9 @@ class MEDIA_EXPORT AudioOutputController
   // audio_power_monitor.h for usage.  This may be called on any thread.
   std::pair<float, bool> ReadCurrentPowerAndClip();
 
+  // Accessor for enabling communication to the reader.
+  SyncReader* reader() { return sync_reader_.get(); }
+
  protected:
   // Internal state of the source.
   enum State {
@@ -207,10 +212,11 @@ class MEDIA_EXPORT AudioOutputController
   ~AudioOutputController() override;
 
  private:
-  AudioOutputController(AudioManager* audio_manager, EventHandler* handler,
+  AudioOutputController(AudioManager* audio_manager,
+                        EventHandler* handler,
                         const AudioParameters& params,
                         const std::string& output_device_id,
-                        SyncReader* sync_reader);
+                        std::unique_ptr<SyncReader> sync_reader);
 
   // The following methods are executed on the audio manager thread.
   void DoCreate(bool is_for_device_change);
@@ -263,7 +269,7 @@ class MEDIA_EXPORT AudioOutputController
   State state_;
 
   // SyncReader is used only in low latency mode for synchronous reading.
-  SyncReader* const sync_reader_;
+  const std::unique_ptr<SyncReader> sync_reader_;
 
   // The message loop of audio manager thread that this object runs on.
   const scoped_refptr<base::SingleThreadTaskRunner> message_loop_;