Always return a WP_Theme object from wp_get_theme(). If we can't find the...

Always return a WP_Theme object from wp_get_theme(). If we can't find the theme root, assume the default theme root. (Which will probably result in a WP_Theme object that returns false for the exists() method, which is fine.) see #20361.



git-svn-id: https://core.svn.wordpress.org/trunk@20524 1a063a9b-81f0-0310-95a4-ce76da25c4cd