https://drafts.csswg.org/css-contain-3/#container-type
Created attachment 449810 [details] Patch
Created attachment 449819 [details] Patch
Created attachment 449847 [details] Patch for landing
Committed r288465 (246351@main): <https://commits.webkit.org/246351@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 449847 [details].
<rdar://problem/87989276>
(In reply to EWS from comment #4) > Committed r288465 (246351@main): <https://commits.webkit.org/246351@main> This broke two layout-tests on ios-wk2. https://results.webkit.org/?suite=layout-tests&test=imported%2Fw3c%2Fweb-platform-tests%2Fcss%2Fcssom%2FgetComputedStyle-detached-subtree.html https://results.webkit.org/?suite=layout-tests&test=imported%2Fw3c%2Fweb-platform-tests%2Fcss%2Fcss-contain%2Fcontainer-queries%2Fcontainer-type-containment.html EWS also indicated that on previous patch on this bug in https://ews-build.webkit.org/#/builders/68/builds/6336, and many EWSes were red. Still, the newer patch was landed without even running through EWS.
Rebased tests for iOS here: https://trac.webkit.org/changeset/288574/webkit