Enforce non-negative BitstreamBuffer id

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 <list>
 #include <map>
 #include <utility>
@@ skipping 200 matching lines @@
     int32 bitstream_buffer_id;
     base::TimeDelta timestamp;
     gfx::Rect visible_rect;
     gfx::Size natural_size;
   };
   std::list<BufferData> input_buffer_data_;
 
   // picture_buffer_id and the frame wrapping the corresponding Picture, for
   // frames that have been decoded but haven't been requested by a Read() yet.
   std::list<scoped_refptr<VideoFrame> > ready_video_frames_;
-  int64 next_picture_buffer_id_;
-  int64 next_bitstream_buffer_id_;
+  int32 next_picture_buffer_id_;
+  int32 next_bitstream_buffer_id_;
 
   // Indicates decoding error occurred.
   bool error_occured_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuVideoDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_GPU_VIDEO_DECODER_H_