Shrink EventTargetData by making firingEventListeners vector optional.
<rdar://problem/12515099>
Created attachment 169077 [details] poch
Comment on attachment 169077 [details] poch Is gud poch.
Comment on attachment 169077 [details] poch Clearing flags on attachment: 169077 Committed r131620: <http://trac.webkit.org/changeset/131620>
All reviewed patches have been landed. Closing bug.