gpu: Swap chain front buffer test

Test that front buffer has expected contents after present.

Bug: 939655
Change-Id: I5a3e89655e1ae20e04ab7463a6ad9d4040a57002
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1717653
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Commit-Queue: Sunny Sachanandani <sunnyps@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681040}
1 file changed