Currently, the tests in chrome/browser/ui/webui/interstitials/interstitial_ui_browsertest.cc only test that the various interstitials have the correct header. (For example, SSL interstitials should read "Privacy error.")

Ideally we want to flesh out these tests a little more. One option is to actually check the text content of the interstitial. The method IsInterstitialDisplayingText() could be helpful for this. Another option would be to check that the correct graphic is showing, etc.