Adding callback support to media filter Initialize() and Seek().

media/filters/audio_renderer_base.h

Index: media/filters/audio_renderer_base.h
diff --git a/media/filters/audio_renderer_base.h b/media/filters/audio_renderer_base.h
index e3ec686d15b65567aba7031bba65acea6c031307..3d314746a4ea0874f3abf5e6f901f6b4e1274b28 100644
--- a/media/filters/audio_renderer_base.h
+++ b/media/filters/audio_renderer_base.h
@@ -32,10 +32,10 @@ class AudioRendererBase : public AudioRenderer {
   // MediaFilter implementation.
   virtual void Stop();
 
-  virtual void Seek(base::TimeDelta time);
+  virtual void Seek(base::TimeDelta time, FilterCallback* callback);
 
   // AudioRenderer implementation.
-  virtual bool Initialize(AudioDecoder* decoder);
+  virtual void Initialize(AudioDecoder* decoder, FilterCallback* callback);
 
  protected:
   // The default maximum size of the queue.
@@ -116,6 +116,9 @@ class AudioRendererBase : public AudioRenderer {
   // TODO(ralphl): Update this value after seeking.
   base::TimeDelta last_fill_buffer_time_;
 
+  // Filter callbacks.
+  scoped_ptr<FilterCallback> initialize_callback_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioRendererBase);
 };