The culprit is one line in CSSStyleSelector::pushParentElement(): changing from parentOrHostElement() to parentOrHostNode(), causing a 20% perf regression in Parser/html5-full-render.html.
Created attachment 130346 [details]
Created attachment 130348 [details]
Comment on attachment 130348 [details]
Clearing flags on attachment: 130348
Committed r109906: <http://trac.webkit.org/changeset/109906>
All reviewed patches have been landed. Closing bug.