DOMUI prefs: Fix missing unload listener on the homepage field
DOMUI prefs: Fix missing unload listener on the homepage field

We used to get this for free as part of the pref-linking object decoration, but after the fixes for managed preferences the URL field is no longer a pref-linked field, so we need to add the unload handler directly.

BUG=60636
TEST=Change the homepage in DOMUI prefs, and close the tab without changing focus.

Review URL: http://codereview.chromium.org/4119002

git-svn-id: http://src.chromium.org/svn/trunk/src@63915 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: f3463cb7bd2598fb114c22ea24ad47fd089f0b69
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