merge_pr_9964
This patch adds support for scroll-margin-* and adds relevant tests. Spec: https://drafts.csswg.org/css-scroll-snap-1/#margin-longhands-physical Bug: 820299 Change-Id: I46f8482c88c237de2a9d263b3a334ac9c03f4fca Reviewed-on: https://chromium-review.googlesource.com/958755 Reviewed-by: nainar <[email protected]> Commit-Queue: Darren Shen <[email protected]> Cr-Commit-Position: refs/heads/master@{#543004}