See: https://webkit.org/?p=7846&preview=true The bad rendering in that page is in the "Transition Thread Locality and Flat Butterflies" section.
Created attachment 317464 [details] Patch
Comment on attachment 317464 [details] Patch Clearing flags on attachment: 317464 Committed r220360: <http://trac.webkit.org/changeset/220360>
All reviewed patches have been landed. Closing bug.
<rdar://problem/33763487>