GitLab

This patch updates four web platform tests involving CSS highlight
painting order, which should help us rework our highlight paint code
to comply with css-pseudo.

• css/css-pseudo/selection-overlay-and-{grammar,spelling}-001.html
    • two manual tests, checking the relative painting order of
      ::selection and ::{grammar,spelling}-error overlays
    • added @contenteditable/@spellcheck/@lang to test element
    • added Selection#removeAllRanges call to work around API change
    • replaced the grammar test sentence with a more obvious example
    • rewrote most of the comments for clarity

• css/css-pseudo/highlight-painting-order.html
    • new reftest, checking relative painting order of text, original
      shadows, ::selection background, and ::selection shadows
    • based on <https://bucket.daz.cat/work/igalia/0/3.html>

• css/css-pseudo/selection-text-shadow-{006-manual,016{,-ref}}.html
    • one manual test, one reftest, checking that text-shadow:none in
      ::selection suppresses all original shadows (even if multiple)
    • dropped because they are no longer compliant (highlight overlays
      have their own shadows, independent of the content’s shadows)

Bug: 1147859
Change-Id: I29bab589e3924778d555d96537d010dc33ed003f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2624328
Commit-Queue: Delan Azabani <dazabani@igalia.com>
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843482}