Rethrow cross-site exceptions as security errors

      BUG=530301
R=epertoso@chromium.org,haraken@chromium.org

Review URL: https://codereview.chromium.org/1339023002

git-svn-id: svn://svn.chromium.org/blink/trunk@202211 bbb929c8-8fbe-4397-9dbb-9b2b20218538