Gets the entity controller class for an entity type.
Drupal\Core\Entity\EntityStorageControllerInterface
function entity_get_controller($entity_type) {
$controllers =& drupal_static(__FUNCTION__, array());
if (!isset($controllers[$entity_type])) {
$type_info = entity_get_info($entity_type);
$class = $type_info['controller_class'];
$controllers[$entity_type] = new $class($entity_type);
}
return $controllers[$entity_type];
}