commit d5c56ea70444a166aade595cd43a7156241df569
Author: Joel Pittet <joel@pittet.ca>
Date:   Wed May 27 21:36:54 2015 -0700

    fix

diff --git a/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeWidgetBase.php b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeWidgetBase.php
index 1a7c434..32d3668 100644
--- a/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeWidgetBase.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeWidgetBase.php
@@ -11,7 +11,6 @@
 use Drupal\Core\Field\FieldItemListInterface;
 use Drupal\Core\Field\WidgetBase;
 use Drupal\Core\Form\FormStateInterface;
-use Drupal\Core\Template\Attribute;
 use Drupal\datetime\Plugin\Field\FieldType\DateTimeItem;
 
 /**
@@ -29,9 +28,7 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
     // title because the actual title display is handled at a higher level by
     // the Field module.
 
-    $element['#theme_wrappers']['datetime_wrapper'] = [
-      '#title_attributes' => new Attribute(),
-    ];
+    $element['#theme_wrappers'][] = 'datetime_wrapper';
     $element['#attributes']['class'][] = 'container-inline';
 
     $element['value'] = array(