media/gpu shared memory: Update fake UnalignedSharedMemory.

Uses the new WritableUnalignedMapping class, which changes the ownership
semantics. See the bug for details on the overall plan.

Bug: 849207
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I84bf28d0da5b6c6d9e764b6f30d48f263550e37f
Reviewed-on: https://chromium-review.googlesource.com/1117689Reviewed-by: Dan Sanders <sandersd@chromium.org>
Commit-Queue: Matthew Cary <mattcary@chromium.org>
Cr-Commit-Position: refs/heads/master@{#571872}

media/gpu/fake_jpeg_decode_accelerator.cc

@@ -41,10 +41,13 @@ void FakeJpegDecodeAccelerator::Decode(
     const scoped_refptr<VideoFrame>& video_frame) {
   DCHECK(io_task_runner_->BelongsToCurrentThread());
 
-  // src_shm will take over the |bitstream_buffer.handle()|.
-  std::unique_ptr<UnalignedSharedMemory> src_shm(new UnalignedSharedMemory(
-      bitstream_buffer.handle(), bitstream_buffer.size(), true));
-  if (!src_shm->MapAt(bitstream_buffer.offset(), bitstream_buffer.size())) {
+  std::unique_ptr<WritableUnalignedMapping> src_shm(
+      new WritableUnalignedMapping(bitstream_buffer.handle(),
+                                   bitstream_buffer.size(),
+                                   bitstream_buffer.offset()));
+  // The handle is no longer needed.
+  bitstream_buffer.handle().Close();
+  if (!src_shm->IsValid()) {
     DLOG(ERROR) << "Unable to map shared memory in FakeJpegDecodeAccelerator";
     NotifyError(bitstream_buffer.id(), JpegDecodeAccelerator::UNREADABLE_INPUT);
     return;
@@ -60,7 +63,7 @@ void FakeJpegDecodeAccelerator::Decode(
 void FakeJpegDecodeAccelerator::DecodeOnDecoderThread(
     const BitstreamBuffer& bitstream_buffer,
     const scoped_refptr<VideoFrame>& video_frame,
-    std::unique_ptr<UnalignedSharedMemory> src_shm) {
+    std::unique_ptr<WritableUnalignedMapping> src_shm) {
   DCHECK(decoder_task_runner_->BelongsToCurrentThread());
 
   // Do not actually decode the Jpeg data.

media/gpu/fake_jpeg_decode_accelerator.h

@@ -22,8 +22,6 @@ class SingleThreadTaskRunner;
 
 namespace media {
 
-class UnalignedSharedMemory;
-
 // Uses software-based decoding. The purpose of this class is to enable testing
 // of communication to the JpegDecodeAccelerator without requiring an actual
 // hardware decoder.
@@ -43,7 +41,7 @@ class MEDIA_GPU_EXPORT FakeJpegDecodeAccelerator
  private:
   void DecodeOnDecoderThread(const BitstreamBuffer& bitstream_buffer,
                              const scoped_refptr<VideoFrame>& video_frame,
-                             std::unique_ptr<UnalignedSharedMemory> src_shm);
+                             std::unique_ptr<WritableUnalignedMapping> src_shm);
   void NotifyError(int32_t bitstream_buffer_id, Error error);
   void NotifyErrorOnClientThread(int32_t bitstream_buffer_id, Error error);
   void OnDecodeDoneOnClientThread(int32_t input_buffer_id);