Add a second line of defense against URL spoofs, killing the renderer instead.

      BUG=86758
TEST=Shouldn't be reached.


Review URL: http://codereview.chromium.org/7483002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@93828 0039d316-1c4b-4281-b951-d872f2087c98