CSS: WPT for basic-shape <position> parsing

Test that basic shapes support the <position> grammar
https://drafts.csswg.org/css-shapes/#typedef-basic-shape
https://drafts.csswg.org/css-values-4/#typedef-position

and not the additional forms allowed by the <bg-position> grammar
https://drafts.csswg.org/css-backgrounds-3/#propdef-background-position

Blink has deprecated <bg-position> support in basic shapes
(and other contexts other than background-position), so the expected
failures are while we wait for removal in M68.

BUG=804187

Change-Id: Ifcaa72f42f2b63730ec761bf4fff4d4557f82b75
Reviewed-on: https://chromium-review.googlesource.com/897071
Reviewed-by: nainar <nainar@chromium.org>
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533849}
3 files changed