Mimic a static HTML file from Wordpress using functions.php

gistfile1.php

/* When an html page like URL is accessed, return some static content,
     In this case, a verification page for Google Apps 

In the current theme functions.php:
*/
if( !class_exists('google_verify') ) {
    class google_verify {
        public function __construct() {
            add_filter('rewrite_rules_array', array($this,'gv_rewrite') );
            if( !is_admin() ) {
                add_filter('query_vars', array($this,'gv_queryvars') );
                add_filter('wp_headers', array($this,'gv_output') );
            }
        }

        public function gv_queryvars($qvars) {
            $qvars[] = 'gv_flag';
            return $qvars;
        }

        public function gv_rewrite($wprw = array()) {
            return array('googlehostedservice.html/?$' => 'index.php?gv_flag=1') + $wprw;
        }

        public function gv_output($headers) {
            global $wp;
            if( !empty($wp->query_vars) and isset($wp->query_vars['gv_flag']) and $wp->query_vars['gv_flag'] == 1 ) {
                die('google4255e00b32ef3c4');
            }
        }
    }
    $google_verify = new google_verify();
}