Update mask-image-3-ref.html to not use mask

[progers]

Test List

mask-image-3a.html mask-image-3b.html mask-image-3c.html mask-image-3d.html mask-image-3e.html mask-image-3f.html mask-image-3g.html mask-image-3h.html mask-image-3i.html

Rationale

mask-image-3-ref.html is the reference file for several mask-image tests (list), and the reference itself uses mask. Engines that have not yet fully masked up incorrectly pass (Blink and Webkit).

This test change proposal is to make this reference file not use mask. It will cause Chromium and Safari to start failing some of these tests (Firefox will continue to pass), and it will make it easier to fix these.

Proposed change: https://github.com/web-platform-tests/wpt/pull/42555

@nt1m @dholbert

[progers]

This proposal follows this guidance to the letter, but it seems unlikely to be controversial, and may be a waste of everyone's time. Would you all like me to file test change proposals for clear-cut cases like this (e.g., maybe it helps you triage new failures?), or would you like me to just land them with reasonable commit messages?

[nt1m]

This looks fine to me. I appreciate notifying when test changes affect other browsers results :)

Could you leave a link to the Chromium fix once you have one?

[progers]

Sure thing! I went ahead and landed this in https://chromium.googlesource.com/chromium/src/+/0f2790d0a18ba66d84ca038e605cadc200662364

[dholbert]

Thanks for the heads-up!