Convert Filter::Seek() to use new callback system.

media/base/filters.h

 // Copyright (c) 2011 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.
 
 // Filters are connected in a strongly typed manner, with downstream filters
 // always reading data from upstream filters.  Upstream filters have no clue
 // who is actually reading from them, and return the results via callbacks.
 //
 //                         DemuxerStream(Video) <- VideoDecoder <- VideoRenderer
 // DataSource <- Demuxer <
@@ skipping 15 matching lines @@
 #include <limits>
 #include <string>
 
 #include "base/callback.h"
 #include "base/callback_old.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time.h"
 #include "media/base/audio_decoder_config.h"
 #include "media/base/media_format.h"
+#include "media/base/pipeline_status.h"
 #include "media/base/video_frame.h"
 
 struct AVStream;
 
 namespace media {
 
 class Buffer;
 class Decoder;
 class DemuxerStream;
 class Filter;
 class FilterHost;
 
 struct PipelineStatistics;
 
 // Used to specify video preload states. They are "hints" to the browser about
 // how aggressively the browser should load and buffer data.
 // Please see the HTML5 spec for the descriptions of these values:
 // http://www.w3.org/TR/html5/video.html#attr-media-preload
 //
 // Enum values must match the values in WebCore::MediaPlayer::Preload and
 // there will be assertions at compile time if they do not match.
 enum Preload {
   NONE,
   METADATA,
   AUTO,
 };
 
 // Used for completing asynchronous methods.
 typedef Callback0::Type FilterCallback;
+typedef base::Callback<void(PipelineStatus)> FilterStatusCB;
+
+// This function copies |cb|, calls Reset() on |cb|, and then calls Run()
+// on the copy. This is used in the common case where you need to clear
+// a callback member variable before running the callback.
+void ResetAndRunCB(FilterStatusCB* cb, PipelineStatus status);
 
 // Used for updating pipeline statistics.
 typedef Callback1<const PipelineStatistics&>::Type StatisticsCallback;
 
 class Filter : public base::RefCountedThreadSafe<Filter> {
  public:
   Filter();
 
   // Sets the private member |host_|. This is the first method called by
   // the FilterHost after a filter is created.  The host holds a strong
@@ skipping 22 matching lines @@
   // the client called Stop().
   // TODO(boliu): Check that callback is not NULL in subclasses.
   virtual void Stop(FilterCallback* callback);
 
   // The pipeline playback rate has been changed.  Filters may implement this
   // method if they need to respond to this call.
   virtual void SetPlaybackRate(float playback_rate);
 
   // Carry out any actions required to seek to the given time, executing the
   // callback upon completion.
-  virtual void Seek(base::TimeDelta time, FilterCallback* callback);
+  virtual void Seek(base::TimeDelta time, const FilterStatusCB& callback);
 
   // This method is called from the pipeline when the audio renderer
   // is disabled. Filters can ignore the notification if they do not
   // need to react to this event.
   virtual void OnAudioRendererDisabled();
 
  protected:
   // Only allow scoped_refptr<> to delete filters.
   friend class base::RefCountedThreadSafe<Filter>;
   virtual ~Filter();
@@ skipping 175 matching lines @@
   // buffer.
   virtual bool HasEnded() = 0;
 
   // Sets the output volume.
   virtual void SetVolume(float volume) = 0;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_FILTERS_H_