We have been implementing constructors of Events. PopStateEvent has a constructor in JSC (https://bugs.webkit.org/show_bug.cgi?id=67977), but do not have it in V8.
Created attachment 108834 [details] Patch
Created attachment 108990 [details] rebased patch for commit
Comment on attachment 108990 [details] rebased patch for commit Clearing flags on attachment: 108990 Committed r96212: <http://trac.webkit.org/changeset/96212>