Set theme immediately on change.
Set theme immediately on change.

BUG=none
TEST=reset theme; watch window immediately retheme

Review URL: http://codereview.chromium.org/149752

git-svn-id: http://src.chromium.org/svn/trunk/src@20865 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: fe19f947fa5382ac9194cf1d71e49d9db1073a61
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