UIProcess crash in WebPageProxy::reattachToWebProcess when web process crashes with a new tab/window.

Reviewed by Darin Adler.

* UIProcess/WebPageProxy.cpp:
(WebKit::WebPageProxy::reattachToWebProcessWithItem): Null check item *both* places it is used.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@76089 268f45cc-cd09-0410-ab3c-d52691b4dbfc