Port CSS keywords in longhands CSS properties to CSSValueID

CSSValueID was changed to an scoped enum in https://crrev.com/c/1530916,
and equivalent int variables were introduced while the remaining uses
were ported. This CL ports the keyword values in

Bug: 936371
Change-Id: I3bd83971f8cd5345b93f00a59ffaed6b6c5806f2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1532014
Commit-Queue: Henrique Ferreiro <hferreiro@igalia.com>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#643730}
102 files changed