Use the size of the underlying bitstream buffer and not the memory region size...

Use the size of the underlying bitstream buffer and not the memory region size when creating the media::BitstreamBuffer

Change-Id: I195daf984595fb27f22401ff4ad1a4220805cfde

Bug: 1013437
Change-Id: I195daf984595fb27f22401ff4ad1a4220805cfde
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1850971
Commit-Queue: Matthew Cary (CET) <mattcary@chromium.org>
Reviewed-by: Matthew Cary (CET) <mattcary@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#705154}

content/renderer/pepper/ppb_video_decoder_impl.cc

@@ -166,7 +166,7 @@ int32_t PPB_VideoDecoder_Impl::Decode(
   // but only after PPB_Buffer_Impl is updated to deal with that.
   media::BitstreamBuffer decode_buffer(bitstream_buffer->id,
                                        buffer->shared_memory().Duplicate(),
-                                       buffer->shared_memory().GetSize());
+                                       bitstream_buffer->size);
   if (!SetBitstreamBufferCallback(bitstream_buffer->id, callback))
     return PP_ERROR_BADARGUMENT;