Notification objects can outlive the page they are in. If the ScriptExecutionContext that created the notification was destroyed, don't invoke "display" or "close" events on the notification object. When running inside DRT, also don't log after the ScriptExecutionContext was destroyed. I actually don't understand why this is not causing failures on the build bot.
Created attachment 57783 [details] Patch.
Comment on attachment 57783 [details] Patch. Looks good to me. r+.
Committed r60630: <http://trac.webkit.org/changeset/60630>
Revision r60630 cherry-picked into qtwebkit-2.1 with commit 7c263035b4010a8c7cf057eb7d2ba0fdd336929d