[carousel] Implement scroll-marker-contain property logic

This CL adds logic to collect html anchor element to
scroll-marker-contain containers to support scroll tracking to determine
the active one.

When we detect any element with scroll-marker-contain property we mark
Document that it needs to do an extra pass to collect all
scroll-marker-contain elements and corresponding anchor elements.

After that collection we subscribe each scroll-marker-contain element's
ScrollMarkerGroupData to each scroller that owns any of group's scroll
targets (e.g. scroll marker is <a href="#target"> then scroll target
is some element with id="target" and scroller is closest ancestor
scroller of scroll target).

This way scrollers will notify scroll marker groups of any scrolls so
that we need to do scroll tracking of active (:target-current) scroll
marker.

This CL also lacks some invalidation logic and invalidation tests, those
will be added together in following CLs.

Bug: 398065922
Change-Id: I9eaa5f6bf0ffb62dded2f45b509964c161f70408
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6357113
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Daniil Sakhapov <sakhapov@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1435932}