HTML5 (living spec/thing/whatever) has renamed this method: http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2013-September/040680.html
<rdar://problem/14914499>
Created attachment 210536 [details] Patch
Comment on attachment 210536 [details] Patch I assume we intentionally do not preserve support for "supportsContext" and just do a rename.
Committed r155137: <http://trac.webkit.org/changeset/155137>