Add offset support to BitstreamBuffer.

content/common/gpu/media/gpu_video_decode_accelerator.cc

Index: content/common/gpu/media/gpu_video_decode_accelerator.cc
diff --git a/content/common/gpu/media/gpu_video_decode_accelerator.cc b/content/common/gpu/media/gpu_video_decode_accelerator.cc
index 5424a5ff32d801d846662f7fb95b910caf19e7ef..7ea77db3551a33bba3d4f8495b23a90a912170fa 100644
--- a/content/common/gpu/media/gpu_video_decode_accelerator.cc
+++ b/content/common/gpu/media/gpu_video_decode_accelerator.cc
@@ -509,9 +509,9 @@ void GpuVideoDecodeAccelerator::OnDecode(
     return;
   }
 
-  media::BitstreamBuffer bitstream_buffer(params.bitstream_buffer_id,
-                                          params.buffer_handle, params.size,
-                                          params.presentation_timestamp);
+  media::BitstreamBuffer bitstream_buffer(
+      params.bitstream_buffer_id, params.buffer_handle, params.size,
+      params.offset, params.presentation_timestamp);

[dcheng, 2016/01/22 18:27:39]

Where do we validate that params.offset can fit in an off_t? What if
params.offset > INT_MAX?

[Pawel Osciak, 2016/01/25 08:20:02]

GNU defines off_t as 32 or 64 bit, so there it would always be ok, but from what
I can see, POSIX only defines off_t as "signed integer type"
(http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_types.h.html),
which I'm not sure guarantees 32 bits. I guess we could always checked_cast here
as well to be sure.

[Owen Lin, 2016/01/25 09:30:59]

Good catch, code modified.

   if (!params.key_id.empty()) {
     bitstream_buffer.SetDecryptConfig(
         media::DecryptConfig(params.key_id, params.iv, params.subsamples));