Provide a list of additional theme functions for the theme information page
public function additionalThemeFunctions() {
$funcs = array();
if (!empty($this->definition['additional themes'])) {
foreach ($this->definition['additional themes'] as $theme => $type) {
$funcs[] = views_theme_functions($theme, $this->view, $this->view->display_handler->display);
}
}
return $funcs;
}