Currently elementParentStyle is not used in SelectorChecker and StyleResolver. A parent style was used to cache whether a child of the parent node matches some n-th, first-child, last-child selector. The information was used to check whether a given element can share its sibling element's style or not. However, now the information is stored in a parent element, not style. So we don't need to provide elementParentStyle for SelectorChecker. (c.f. StyleResolver::parentElementPreventsSharing)
Created attachment 183877 [details] WIP
Created attachment 183878 [details] Patch
(In reply to comment #0) > A parent style was used to cache whether a child of the parent node matches some n-th, first-child, last-child selector. The information was used to check whether a given element can share its sibling element's style or not. I mean, childrenAffectedBy bits were moved from RenderStyle to Element, c.f. https://bugs.webkit.org/show_bug.cgi?id=101448
Comment on attachment 183878 [details] Patch Clearing flags on attachment: 183878 Committed r140531: <http://trac.webkit.org/changeset/140531>
All reviewed patches have been landed. Closing bug.