Provides the name to use for the summary. By default this is just the name field.
$data: The query results for the row.
public function summaryName($data) {
$value = $data->{$this->name_alias};
if (empty($value) && !empty($this->definition['empty field name'])) {
$value = $this->definition['empty field name'];
}
return check_plain($value);
}