https://drafts.csswg.org/css-contain-3/#container-lengths
<rdar://problem/111446508>
Pull request: https://github.com/WebKit/WebKit/pull/15368
Committed 265583@main (fe4a838ddc27): <https://commits.webkit.org/265583@main> Reviewed commits have been landed. Closing PR #15368 and removing active labels.