This is spawned off from Bug 106205. Play trailer video and try to go to fullscreen. Video playback stops and goes black without seeing fullscreen. It was mentioned in the other bug that it looks like a PluginProcess crash.
<rdar://problem/12973955>
Regressed in this range: <http://trac.webkit.org/log/trunk/?rev=138880&stop_rev=138868>
*** This bug has been marked as a duplicate of bug 106347 ***