"Giving an element inline-size containment applies size containment to the inline-axis sizing of its principal box. This means the inline-axis intrinsic sizes of the principal box are determined as if the element had no content." https://drafts.csswg.org/css-contain-3/#containment-inline-size
Created attachment 451349 [details] Patch
Comment on attachment 451349 [details] Patch r=me
Committed r289466 (247009@main): <https://commits.webkit.org/247009@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 451349 [details].
<rdar://problem/88683436>