LayoutState describes the whole layout. We should only have one per tree instead of one per formatting context.
<rdar://problem/100804461>
Created attachment 462809 [details] Patch
Created attachment 462867 [details] Patch for landing
Committed 255277@main (c227d6059a2e): <https://commits.webkit.org/255277@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 462867 [details].