Enforce non-negative BitstreamBuffer id

media/filters/gpu_video_decoder.cc

Index: media/filters/gpu_video_decoder.cc
diff --git a/media/filters/gpu_video_decoder.cc b/media/filters/gpu_video_decoder.cc
index b2e5670336de3485d57b61fb7cb5b1739801c3d3..775faf0bd97ed52df66a61ce01edd419fe454e8e 100644
--- a/media/filters/gpu_video_decoder.cc
+++ b/media/filters/gpu_video_decoder.cc
@@ -284,7 +284,8 @@ void GpuVideoDecoder::RequestBufferDecode(
   SHMBuffer* shm_buffer = GetSHM(size);
   memcpy(shm_buffer->shm->memory(), buffer->GetData(), size);
   BitstreamBuffer bitstream_buffer(
-      next_bitstream_buffer_id_++, shm_buffer->shm->handle(), size);
+      next_bitstream_buffer_id_, shm_buffer->shm->handle(), size);
+  next_bitstream_buffer_id_ = (next_bitstream_buffer_id_ + 1) & 0x3FFFFFFF;

[Ami GONE FROM CHROMIUM, 2013/01/10 23:41:31]

Weird enough to deserve a comment.  Note that here (unlike the test) n_b_b_i_ is
an int64, so the previous code was actually fine.  If you want to keep this
3FFFFFFF then probably best to make n_b_b_i_ int32 here, too.

   bool inserted = bitstream_buffers_in_decoder_.insert(std::make_pair(
       bitstream_buffer.id(), BufferPair(shm_buffer, buffer))).second;
   DCHECK(inserted);