preparation for recycling buffer, patch 2

media/filters/video_decode_engine.h

 // Copyright (c) 2010 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_FILTERS_VIDEO_DECODE_ENGINE_H_
 #define MEDIA_FILTERS_VIDEO_DECODE_ENGINE_H_
 
 #include "base/callback.h"
 #include "base/message_loop.h"
 #include "media/base/video_frame.h"
 
 // FFmpeg types.
 //
 // TODO(ajwong): Try to cut the dependency on the FFmpeg types.
 struct AVStream;
 
 class Task;
 
 namespace media {
 
 class Buffer;
 
 class VideoDecodeEngine {
  public:
   enum State {
     kCreated,
     kNormal,
     kStopped,
+    kFlushing,
     kError,
   };
 
   VideoDecodeEngine() {}
   virtual ~VideoDecodeEngine() {}
 
   // This calback is called by the decode engine to notify that the decode
   // engine has consumed an input bufer in response to a EmptyThisBuffer() call.
   typedef Callback1<scoped_refptr<Buffer> >::Type EmptyThisBufferCallback;
 
@@ skipping 19 matching lines @@
   // of the decoder reordering delay and jittery removal requirements. Input
   // buffers are returned into engine through |EmptyThisBuffer|.
   // 2. Output buffers are provided from outside the engine, and feed into
   // engine through |FillThisBuffer|. Output buffers are returned to outside
   // by |FillThisBufferCallback|.
   virtual void EmptyThisBuffer(scoped_refptr<Buffer> buffer) = 0;
   virtual void FillThisBuffer(scoped_refptr<VideoFrame> frame) = 0;
 
   virtual void Stop(Task* done_cb) = 0;
   virtual void Pause(Task* done_cb) = 0;
+  virtual void Seek(Task* done_cb) = 0;
 
   // Flushes the decode engine of any buffered input packets.
   virtual void Flush(Task* done_cb) = 0;
 
   // Returns the VideoSurface::Format of the resulting |yuv_frame| from
   // DecodeFrame().
   virtual VideoFrame::Format GetSurfaceFormat() const = 0;
 
+  virtual bool ProvidesBuffer() const = 0;
+
   // Returns the current state of the decode engine.
   virtual State state() const  = 0;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_VIDEO_DECODE_ENGINE_H_