[css-properties-values-api] Typify CSSStyleValue.parse/All.

Passing the PropertyRegistration makes StyleValueFactory::FromString
find the typed value, and create appropriate and corresponding TypedOM
types.

Note: the check on property_id==CSSPropertyVariable isn't strictly
required, but it's nice to avoid the AtomicString creation if we know it's
not needed.

R=futhark@chromium.org

Bug: 641877
Change-Id: Id7f7f8c754f8aab7f64a92efd896243858d03757
Reviewed-on: https://chromium-review.googlesource.com/1199182
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Anders Ruud <andruud@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588001}
4 files changed