See https://github.com/w3c/csswg-drafts/issues/8407.
Pull request: https://github.com/WebKit/WebKit/pull/16226
<rdar://problem/113499441>
Committed 267180@main (3c2445f3450d): <https://commits.webkit.org/267180@main> Reviewed commits have been landed. Closing PR #16226 and removing active labels.