Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

core/modules/taxonomy/src/VocabularyStorage.php

@@ -0,0 +1,33 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\taxonomy\VocabularyStorage.
+ */
+
+namespace Drupal\taxonomy;
+
+use Drupal\Core\Cache\Cache;
+use Drupal\Core\Config\Entity\ConfigEntityStorage;
+
+/**
+ * Defines a controller class for taxonomy vocabularies.
+ */
+class VocabularyStorage extends ConfigEntityStorage implements VocabularyStorageInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function resetCache(array $ids = NULL) {
+    drupal_static_reset('taxonomy_vocabulary_get_names');
+    parent::resetCache($ids);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getToplevelTids($vids) {
+    return db_query('SELECT t.tid FROM {taxonomy_term_data} t INNER JOIN {taxonomy_term_hierarchy} th ON th.tid = t.tid WHERE t.vid IN ( :vids[] ) AND th.parent = 0', array(':vids[]' => $vids))->fetchCol();
+  }
+
+}