Port CSS keyword int values in core/css/parser 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 all the keyword values in
third_party/blink/renderer/core/css/parser.

Bug: 936371
Change-Id: I5d4da5aad6204c3ab6e9875d3b9977a374ab3658
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1530919
Commit-Queue: Henrique Ferreiro <hferreiro@igalia.com>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#643724}
11 files changed