[carousel] Add tabs/links mode to CSS scroll-marker-group property
This CL adds just parsing of tabs/links mode for scroll-marker-group
property. No behaviour changes.
This change is to experiment and draft the spec behaviour
of different modes of navigation/a11y for ::scroll-marker
Spec discussion:
https://github.com/w3c/csswg-drafts/issues/12122
TESTS=third_party/blink/web_tests/external/wpt/css/css-overflow/
Bug: 425931511
Change-Id: I14abfd31e2639a5996727ca5307af9574ddbcc14
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6728654
Reviewed-by: Robert Flack <flackr@chromium.org>
Commit-Queue: Daniil Sakhapov <sakhapov@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1485695}
