Revert "[media] Add interface for VDAs to Decode() media::DecoderBuffers."

This reverts commit 4596c80251c8c66e2335ca01f56eba4621952dc7.

Reason for revert: UnalignedSharedMemoryTest failing on multiple bots.

Original change's description:
> [media] Add interface for VDAs to Decode() media::DecoderBuffers.
> 
> Using DecoderBuffer removes the need to provided SharedMemoryHandles in
> cases that SharedMemory is not already allocated (in particular, when
> VDAs are used through MojoVideoDecoder+VdaVideoDecoder). Since
> base::SharedMemory is not an interface, a new type is required, and
> DecoderBuffer already implements a suitable interface for this use case.
> 
> This CL adds:
>   - A VideoDecodeAccelerator::Decode() overload for decoding
>     DecoderBuffers, which VDAs may optionally implement.
>     Note that VdaVideoDecoder will require this, and therefore all VDAs
>     will be updated to support DecoderBuffers over time.
>   - Support for SHM in DecoderBuffer. This eases the transition by
>     allowing BitstreamBuffers to be easily converted to equivalent
>     DecoderBuffers.
>   - An implementation of the new VideoDecodeAccelerator::Decode()
>     overload in VTVideoDecodeAccelerator.
>   - Calling the new overload from VdaVideoDecoder.
> 
> Bug: 522298
> 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: Ib932c3524b37e339f592b150685937ea94d4199d
> Reviewed-on: https://chromium-review.googlesource.com/1015965
> Reviewed-by: Pawel Osciak <posciak@chromium.org>
> Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
> Commit-Queue: Dan Sanders <sandersd@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#553364}

TBR=posciak@chromium.org,dalecurtis@chromium.org,sandersd@chromium.org

Change-Id: Iad674ebb5286d5f068b2fc7bb6c67ab5f9a26fc0
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 522298
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
Reviewed-on: https://chromium-review.googlesource.com/1026914
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553456}
19 files changed