CSS: Parsing tests for flood-color

flood-color accepts <<color>> values.
https://drafts.fxtf.org/filter-effects/#propdef-flood-color

The computed flood-color value for rgb() and rgba() is as specified.
The computed flood-color value for color keywords, hex values
and 'transparent' is an rgb() or rgba() function.
https://drafts.csswg.org/css-color-3/#foreground

Change-Id: Iae210734d3829964ad64ae4a7ba7899c391b1898
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1619518
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Auto-Submit: Eric Willigers <ericwilligers@chromium.org>
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661305}
3 files changed