Existing hardware decoders support only YUV 4:2:0 videos. We
currently rely the underlying libraries and drivers to deny non
YUV 4:2:0 videos. We would rater confirm it in
AcceleratedVideoDecoder. From this CL,
AcceleratedVideoDecoder::Decode() returns kDecodeError if
a video is not YUV 4:2:0.

Bug: b:172223934
Test: media_unittests
Change-Id: Ib0ddbe526a801476e382f0b7665a74573bd6a28d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2562618
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Miguel Casas <mcasas@chromium.org>
Reviewed-by: Andres Calderon Jaramillo <andrescj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833594}