Implement flushing in VTVideoDecodeAccelerator.

content/common/gpu/media/vt_video_decode_accelerator.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 CONTENT_COMMON_GPU_MEDIA_VT_VIDEO_DECODE_ACCELERATOR_H_
 #define CONTENT_COMMON_GPU_MEDIA_VT_VIDEO_DECODE_ACCELERATOR_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 46 matching lines @@
 
  private:
   struct DecodedFrame {
     DecodedFrame(int32_t bitstream_id, CVImageBufferRef image_buffer);
     ~DecodedFrame();
 
     int32_t bitstream_id;
     base::ScopedCFTypeRef<CVImageBufferRef> image_buffer;
   };
 
+  enum State {
+    // TODO(sandersd): Size changing state.
+    NORMAL,
+    FLUSHING,
+    RESETTING,
+    DESTROYING,
+  };
+
   // Methods for interacting with VideoToolbox. Run on |decoder_thread_|.
   void ConfigureDecoder(
       const std::vector<const uint8_t*>& nalu_data_ptrs,
       const std::vector<size_t>& nalu_data_sizes);
   void DecodeTask(const media::BitstreamBuffer);
+  void FlushTask();
 
   // Methods for interacting with |client_|. Run on |gpu_task_runner_|.
   void OutputTask(DecodedFrame frame);
   void SizeChangedTask(gfx::Size coded_size);
   void SendPictures();
+  void FlushStart(State state);
+  void FlushDone();
 
   //
   // GPU thread state.
   //
   CGLContextObj cgl_context_;
   media::VideoDecodeAccelerator::Client* client_;
   gfx::Size texture_size_;
+  State state_;
+  int32_t frames_pending_decode_;
 
   // Texture IDs of pictures.
   // TODO(sandersd): A single map of structs holding picture data.
   std::map<int32_t, uint32_t> texture_ids_;
 
   // Pictures ready to be rendered to.
   std::queue<int32_t> available_picture_ids_;
 
   // Decoded frames ready to render.
   std::queue<DecodedFrame> decoded_frames_;
@@ skipping 22 matching lines @@
   // Declared last to ensure that all decoder thread tasks complete before any
   // state is destructed.
   base::Thread decoder_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(VTVideoDecodeAccelerator);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_MEDIA_VT_VIDEO_DECODE_ACCELERATOR_H_