Add offset support to BitstreamBuffer.

content/common/gpu/media/gpu_video_decode_accelerator.cc

 // 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.
 
 #include "content/common/gpu/media/gpu_video_decode_accelerator.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 491 matching lines @@
     } else {
       child_task_runner_->PostTask(
           FROM_HERE,
           base::Bind(&GpuVideoDecodeAccelerator::NotifyError,
                      base::Unretained(this),
                      media::VideoDecodeAccelerator::INVALID_ARGUMENT));
     }
     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));
   }
 
   video_decode_accelerator_->Decode(bitstream_buffer);
 }
 
 void GpuVideoDecodeAccelerator::OnAssignPictureBuffers(
     const std::vector<int32_t>& buffer_ids,
@@ skipping 112 matching lines @@
   uncleared_textures_.erase(it);
 }
 
 void GpuVideoDecodeAccelerator::SendCreateDecoderReply(IPC::Message* message,
                                                        bool succeeded) {
   GpuCommandBufferMsg_CreateVideoDecoder::WriteReplyParams(message, succeeded);
   Send(message);
 }
 
 }  // namespace content