Add offset support to BitstreamBuffer.

content/common/gpu/media/vaapi_jpeg_decode_accelerator.cc

 // Copyright 2015 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/vaapi_jpeg_decode_accelerator.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/thread_task_runner_handle.h"
@@ skipping 271 matching lines @@
     const scoped_refptr<media::VideoFrame>& video_frame) {
   DVLOG(3) << __func__;
   DCHECK(io_task_runner_->BelongsToCurrentThread());
   TRACE_EVENT1("jpeg", "Decode", "input_id", bitstream_buffer.id());
 
   DVLOG(4) << "Mapping new input buffer id: " << bitstream_buffer.id()
            << " size: " << bitstream_buffer.size();
   scoped_ptr<base::SharedMemory> shm(
       new base::SharedMemory(bitstream_buffer.handle(), true));
 
-  if (!shm->Map(bitstream_buffer.size())) {
+  if (!shm->MapAt(bitstream_buffer.offset(), bitstream_buffer.size())) {
     LOG(ERROR) << "Failed to map input buffer";
     NotifyErrorFromDecoderThread(bitstream_buffer.id(), UNREADABLE_INPUT);
     return;
   }
 
   scoped_ptr<DecodeRequest> request(
       new DecodeRequest(bitstream_buffer, shm.Pass(), video_frame));
 
   decoder_task_runner_->PostTask(
       FROM_HERE, base::Bind(&VaapiJpegDecodeAccelerator::DecodeTask,
                             base::Unretained(this), base::Passed(&request)));
 }
 
 bool VaapiJpegDecodeAccelerator::IsSupported() {
   return VaapiWrapper::IsJpegDecodeSupported();
 }
 
 }  // namespace content