Add offset support to BitstreamBuffer.

content/common/gpu/media/v4l2_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 <errno.h>
 #include <linux/videodev2.h>
 #include <sys/mman.h>
 
 #include "base/big_endian.h"
 #include "base/bind.h"
@@ skipping 241 matching lines @@
 
   for (; device_->Ioctl(VIDIOC_ENUM_FMT, &fmtdesc) == 0; ++fmtdesc.index) {
     if (fmtdesc.pixelformat == V4L2_PIX_FMT_JPEG)
       return true;
   }
   return false;
 }
 
 void V4L2JpegDecodeAccelerator::DecodeTask(scoped_ptr<JobRecord> job_record) {
   DCHECK(decoder_task_runner_->BelongsToCurrentThread());
-  job_record->shm.reset(
-      new base::SharedMemory(job_record->bitstream_buffer.handle(), true));
-  if (!job_record->shm->Map(job_record->bitstream_buffer.size())) {
+  media::BitstreamBuffer* buffer = &job_record->bitstream_buffer;
+  job_record->shm.reset(new base::SharedMemory(buffer->handle(), true));
+  if (!job_record->shm->MapAt(buffer->offset(), buffer->size())) {
     PLOG(ERROR) << __func__ << ": could not map bitstream_buffer";
     PostNotifyError(job_record->bitstream_buffer.id(), UNREADABLE_INPUT);
     return;
   }
   input_jobs_.push(make_linked_ptr(job_record.release()));
 
   ServiceDeviceTask(false);
 }
 
 size_t V4L2JpegDecodeAccelerator::InputBufferQueuedCount() {
@@ skipping 608 matching lines @@
   device_poll_thread_.Stop();
 
   // Clear the interrupt now, to be sure.
   if (!device_->ClearDevicePollInterrupt())
     return false;
 
   return true;
 }
 
 }  // namespace content