Consider merging https://chromium.googlesource.com/chromium/blink/+/eb8a1c93a99909c361016e1a8f7bf8734f04120a When a load is cancelled via x-frame-options, we dispatch a load event. The load event might detach the frame, in which case we shouldn't try to access the frameLoader().
<rdar://problem/13977070>
Committed <http://trac.webkit.org/r151812>.