private function registerHtmlIfNeeded()
    {
        if (!$this->app->offsetExists('html')) {

            $this->app->singleton('html', function($app) {
                return new HtmlBuilder($app['url'], $app['view']);
            });

            if (! $this->aliasExists('Html')) {

                AliasLoader::getInstance()->alias(
                    'Html',
                    'Collective\Html\HtmlFacade'
                );
            }
        }
    }