https://www.w3.org/TR/css-sizing-3/#box-sizing
Created attachment 416333 [details] Patch
Created attachment 416337 [details] Patch
Committed r270891: <https://trac.webkit.org/changeset/270891> All reviewed patches have been landed. Closing bug and clearing flags on attachment 416337 [details].
<rdar://problem/72385626>