Issue #3405574 by alexpott, borisson_: StorageComparerInterface() is missing...

Issue #3405574 by alexpott, borisson_: StorageComparerInterface() is missing createChangelist() and  docs for StorageComparer::addChangeList(sort_order) are wrong

core/lib/Drupal/Core/Config/StorageComparer.php

@@ -205,9 +205,9 @@ public function getChangelist($op = NULL, $collection = StorageInterface::DEFAUL
    *   The change operation performed. Either delete, create, rename, or update.
    * @param array $changes
    *   Array of changes to add to the changelist.
-   * @param array $sort_order
-   *   Array to sort that can be used to sort the changelist. This array must
-   *   contain all the items that are in the change list.
+   * @param array|null $sort_order
+   *   (optional) Array to sort that can be used to sort the changelist. This
+   *   array must contain all the items that are in the change list.
    */
   protected function addChangeList($collection, $op, array $changes, array $sort_order = NULL) {
     // Only add changes that aren't already listed.

core/lib/Drupal/Core/Config/StorageComparerInterface.php

@@ -65,6 +65,14 @@ public function getEmptyChangelist();
    */
   public function getChangelist($op = NULL, $collection = StorageInterface::DEFAULT_COLLECTION);
 
+  /**
+   * Calculates the differences.
+   *
+   * @return $this
+   *   An object which implements the StorageComparerInterface.
+   */
+  public function createChangelist();
+
   /**
    * Recalculates the differences.
    *