Entity translation controller factory.
string $entity_type: The type of the entity being translated.
\Drupal\translation_entity\EntityTranslationControllerInterface An instance of the entity translation controller interface.
function translation_entity_controller($entity_type) {
$entity_info = entity_get_info($entity_type);
// @todo Throw an exception if the key is missing.
return new $entity_info['controllers']['translation']($entity_type, $entity_info);
}