Evil hack to prevent a crash with interstitials across different tab contents types.
Evil hack to prevent a crash with interstitials across different tab contents types.

BUG=2855
Review URL: http://codereview.chromium.org/9141

git-svn-id: http://src.chromium.org/svn/trunk/src@4717 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 504e1a831b1c28f41b1fb50735d586f99ba0b233
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser