GpuVideoDecoder not to use DemuxerStream after it's stopped.

media/base/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_BASE_VIDEO_DECODER_H_
 #define MEDIA_BASE_VIDEO_DECODER_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "media/base/pipeline_status.h"
@@ skipping 11 matching lines @@
   // Status codes for read operations on VideoDecoder.
   enum Status {
     kOk,  // Everything went as planned.
     kDecodeError,  // Decoding error happened.
     kDecryptError  // Decrypting error happened.
   };
 
   // Initializes a VideoDecoder with the given DemuxerStream, executing the
   // |status_cb| upon completion.
   // |statistics_cb| is used to update the global pipeline statistics.
-  // Note: No VideoDecoder calls should be made before |status_cb| is executed.
+  // Note:
+  // 1) No VideoDecoder calls should be made before |status_cb| is executed.
+  // 2) DemuxerStream should not be accessed after the VideoDecoder is stopped.
   virtual void Initialize(const scoped_refptr<DemuxerStream>& stream,
                           const PipelineStatusCB& status_cb,
                           const StatisticsCB& statistics_cb) = 0;
 
   // Requests a frame to be decoded. The status of the decoder and decoded frame
   // are returned via the provided callback. Only one read may be in flight at
   // any given time.
   //
   // Implementations guarantee that the callback will not be called from within
   // this method.
@@ skipping 36 matching lines @@
   friend class base::RefCountedThreadSafe<VideoDecoder>;
   virtual ~VideoDecoder();
   VideoDecoder();
 
   DISALLOW_COPY_AND_ASSIGN(VideoDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_DECODER_H_