Add usual cleanup code for this sample, fixing breakage with Firefox's backward / forward cache.
Add usual cleanup code for this sample, fixing breakage with Firefox's backward / forward cache.

Review URL: http://codereview.chromium.org/164174

git-svn-id: http://src.chromium.org/svn/trunk/src@22852 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: a322a0db8eff3a6f369b8db0d34d14e1f7f962b4
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