Don't dispatch a "load" event for blocked frames on Safari

For blocked elements on Safari, we manually dispatch an "error" or "load" event, dependent on whether it was a frame or other element. This is required because of cancelling the "beforeload" event doesn't dispatch an "error" event.

But apparently this isn't actually needed for frames, because they already receive a "load" event even when they were blocked.

But the much larger problem is, that manually dispatching a "load" event, triggers "beforeload" again, leading to an infinite recursion, in this case.

[Felix Dahlke, 2014-02-27 21:05:29]

LGTM