[webkit-reviews] review requested: [Bug 49876] Optimize matching of descendant selectors : [Attachment 81133] patch

[bugzilla-daemon at webkit.org]

Antti Koivisto <koivisto at iki.fi> has asked  for review:
Bug 49876: Optimize matching of descendant selectors
https://bugs.webkit.org/show_bug.cgi?id=49876

Attachment 81133: patch
https://bugs.webkit.org/attachment.cgi?id=81133&action=review

------- Additional Comments from Antti Koivisto <koivisto at iki.fi>
During style recalculation, maintain a hash of tags, ids and classes seen in
ancestor elements. Use the hash to quickly reject descendant and child
selectors when doing style matching.

This speeds up style recalculations 3-6x on major web sites.