merge_pr_50221

Make ::scroll-button disabled state snap aware

Scroll buttons should be disabled when snapping prevents any further scrolling
in their intended direction.

Bug: 388545125
Change-Id: I5991f2ff02965a2495a7507d74504b3f213f2657
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6180126
Reviewed-by: Vladimir Levin [email protected]
Reviewed-by: Daniil Sakhapov [email protected]
Commit-Queue: Robert Flack [email protected]
Cr-Commit-Position: refs/heads/main@{#1409802}