GitLab

This change provides overrides for GetYUVA8Planes and QueryYUVA8 so that
the generator can be used as a fake for YUV decoding within unit tests.
It also CHECKs that RGB-only methods are not called within the |is_yuv_|
mode and vice versa, while providing |expect_fallback_to_rgb_| for
future tests/code paths. This is because there does not yet exist
software rendering for YUV, so software fallback goes to RGB.

Bug: 900672
Change-Id: I76bfb744d1beec72939ddb016b0a7abedbde33e7
Reviewed-on: https://chromium-review.googlesource.com/c/1458600
Commit-Queue: Madeleine Barowsky <mbarowsky@chromium.org>
Reviewed-by: Khushal <khushalsagar@chromium.org>
Auto-Submit: Madeleine Barowsky <mbarowsky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#630625}