Index: wp-db.php
===================================================================
--- wp-db.php	(revision 27401)
+++ wp-db.php	(working copy)
@@ -2108,4 +2108,16 @@
 		}
 		return preg_replace( '/[^0-9.].*/', '', $server_info );
 	}
+
+    /**
+     * Returns whether wpdb uses mysqli over mysql.
+     *
+     * @since 3.9.0
+     *
+     * @return bool true if mysqli is used
+     */
+    function uses_mysqli() {
+        return $this->use_mysqli;
+
+    }
 }