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

media/base/renderer.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BASE_RENDERER_H_
 #define MEDIA_BASE_RENDERER_H_
 
 #include "base/callback.h"
 #include "base/time/time.h"
 #include "media/base/buffering_state.h"
 #include "media/base/media_export.h"
 #include "media/base/pipeline_status.h"
 
 namespace media {
 
 class MediaKeys;
 
 class MEDIA_EXPORT Renderer {
  public:
   typedef base::Callback<base::TimeDelta()> TimeDeltaCB;
 
   Renderer();
 
   // Stops rendering and fires any pending callbacks.
   virtual ~Renderer();
 
   // Initializes the Renderer, executing |init_cb| upon completion.
+  // If initialization failed, fires |error_cb| before |init_cb|.
   // TODO(xhwang): Provide a set of DemuxerStreams in Initialize().
-  // TODO(xhwang): Replace |init_cb| with a Closure.
   //
   // Permanent callbacks:
   // - |statistics_cb|: Executed periodically with rendering statistics.
   // - |time_cb|: Executed whenever time has advanced through rendering.
   // - |ended_cb|: Executed when rendering has reached the end of stream.
   // - |error_cb|: Executed if any error was encountered during rendering.
-  virtual void Initialize(const PipelineStatusCB& init_cb,
+  virtual void Initialize(const base::Closure& init_cb,

[tim (not reviewing), 2014/09/03 22:37:26]

How important is it to return PIPELINE_ERROR_INITIALIZATION_FAILED if init
fails? e.g, In a case like I have at https://codereview.chromium.org/518163003,
it was easy before this CL to return that error code without having to add extra
state to my RendererImpl.

[xhwang, 2014/09/03 23:52:37]

I don't quite follow the question.

In you CL, you'll need to plumb in the error_cb_ to your remote_renderer_ (for
other failure cases, e.g. flush error, decoding error). Then you can basically
follow the same model: when init fails, call error_cb first, then fire the
completion callback.

Does that answer your question?

                           const StatisticsCB& statistics_cb,
                           const base::Closure& ended_cb,
                           const PipelineStatusCB& error_cb,
                           const BufferingStateCB& buffering_state_cb,
                           const TimeDeltaCB& get_duration_cb) = 0;
 
   // The following functions must be called after Initialize().
 
   // Discards any buffered data, executing |flush_cb| when completed.
   virtual void Flush(const base::Closure& flush_cb) = 0;
@@ skipping 19 matching lines @@
   // Associates the |cdm| with this Renderer.
   virtual void SetCdm(MediaKeys* cdm) = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(Renderer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_RENDERER_H_