Replace init_cb in Renderer::Initialize() with base::Closure.

media/base/pipeline.h

Index: media/base/pipeline.h
diff --git a/media/base/pipeline.h b/media/base/pipeline.h
index 37d668470b9cd5772a74f839875b80e2a952f621..a5b9e391d4d2e0188d916c29c704dfea66ddedd0 100644
--- a/media/base/pipeline.h
+++ b/media/base/pipeline.h
@@ -260,7 +260,7 @@ class MEDIA_EXPORT Pipeline : public DemuxerHost {
   // Kicks off initialization for each media object, executing |done_cb| with
   // the result when completed.
   void InitializeDemuxer(const PipelineStatusCB& done_cb);
-  void InitializeRenderer(const PipelineStatusCB& done_cb);
+  void InitializeRenderer(const base::Closure& done_cb);
 
   void OnStateTransition(PipelineStatus status);
   void StateTransitionTask(PipelineStatus status);