// The newer api passes the value of the grouping as well.
$sets_new_rendered = $view->style_plugin->renderGrouping($view->result, $view->style_plugin->options['grouping'], TRUE);
// The newer api passes the value of the grouping as well.
$sets_new_rendered = $view->style_plugin->renderGrouping($view->result, $view->style_plugin->options['grouping'], TRUE);