Clarify ownership of GpuVideoDecodeAcceleratorHost and avoid crash on context loss.

media/filters/gpu_video_decoder.h

 // Copyright (c) 2012 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_GPU_VIDEO_DECODER_H_
 #define MEDIA_FILTERS_GPU_VIDEO_DECODER_H_
 
 #include <deque>
 #include <list>
 #include <map>
@@ skipping 107 matching lines @@
   void ReusePictureBuffer(int64 picture_buffer_id);
 
   void RecordBufferTimeData(
       const BitstreamBuffer& bitstream_buffer, const Buffer& buffer);
   base::TimeDelta GetBufferTimestamp(int32 id);
 
   // Set |vda_| and |weak_vda_| on the VDA thread (in practice the render
   // thread).
   void SetVDA(VideoDecodeAccelerator* vda);
 
+  // Call VDA::Destroy() on |vda_loop_proxy_| ensuring that |this| outlives the
+  // Destroy() call.
+  void DestroyVDA();
+
   // A shared memory segment and its allocated size.
   struct SHMBuffer {
     SHMBuffer(base::SharedMemory* m, size_t s);
     ~SHMBuffer();
     base::SharedMemory* shm;
     size_t size;
   };
 
   // Request a shared-memory segment of at least |min_size| bytes.  Will
   // allocate as necessary.  Caller does not own returned pointer.
@@ skipping 72 matching lines @@
 
   // Indicates decoding error occurred.
   bool error_occured_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuVideoDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_GPU_VIDEO_DECODER_H_