revert back document-register-element

src/bundle.js

@@ -4,6 +4,12 @@
 // Use define from require.js not webpack's define
 var _define = window.define;
 
+// document-register-element
+var docRegister = require("document-register-element");
+_define("document-register-element", function() {
+    return docRegister;
+});
+
 // fetch
 var fetch = require("whatwg-fetch");
 _define("fetch", function() {