Upstream http://cl/416087593

lib/legacy/legacy-data-mixin.js

@@ -8,7 +8,6 @@ Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
-import { Class } from './class.js';
 import { Polymer } from '../../polymer-legacy.js';
 import { dedupingMixin } from '../utils/mixin.js';
 import { templatize } from '../utils/templatize.js';
@@ -148,6 +147,7 @@ export const LegacyDataMixin = dedupingMixin(superClass => {
 // LegacyDataMixin is applied to base class _before_ metaprogramming, to
 // ensure override of _addPropertyEffect et.al. are used by metaprogramming
 // performed in _finalizeClass
+const Class = Polymer.Class;
 Polymer.Class = (info, mixin) => Class(info,
   superClass => mixin ?
     mixin(LegacyDataMixin(superClass)) :

lib/utils/wrap.d.ts

@@ -1,4 +1,3 @@
 // tslint:disable:variable-name Describing an API that's defined elsewhere.
 
-
-export {};
+export const wrap: <T extends Node>(node: T) => T;