[css-properties-values-api] Add tests for Typed OM reification.

How registered custom properties are reified is currently not specified
[1]. For computed values, it should hopefully be pretty obvious how it
should work. (For declared/inline style it is less clear).

This patch adds tests for the computed style only.

Note:

 * <transform-function> is not tested, because it appears that this
   syntax was re-added to the spec by mistake, so I expect support for
   <transform-function> will be reverted.
 * <transform-list> and list syntaxes in general are not tested, because
   it's currently broken in Blink. Tests for list syntaxes will be added
   along with the fix for that.

[1] https://drafts.css-houdini.org/css-typed-om-1/#reify-stylevalue

R=chrishtr@chromium.org

Bug: 641877
Change-Id: Ic177bfe2b90897ec44ef4405c745171d8b226e82
Reviewed-on: https://chromium-review.googlesource.com/1134778
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Anders Ruud <andruud@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574858}
1 file changed