protected function _findWebRoot($source)
    {
        $webRootDir = Configure::read('App.webroot');
        $webRoot    = APP_ROOT . DS . $webRootDir . DS;

        list ($plugin, $source) = $this->_View->pluginSplit($source);
        if ($plugin !== null && Plugin::loaded($plugin)) {
            $webRoot = Plugin::path($plugin) . $webRootDir . DS;
        }

        return [FS::clean($webRoot, '/'), $source];
    }