update our CustomElement+Shadow DOM patch

pkg/custom_element/lib/custom-elements.debug.js

 // Copyright (c) 2012 The Polymer Authors. All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //    * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //    * Redistributions in binary form must reproduce the above
 // copyright notice, this list of conditions and the following disclaimer
@@ skipping 1424 matching lines @@
 } else {
   var loadEvent = window.HTMLImports ? 'HTMLImportsLoaded' :
       document.readyState == 'loading' ? 'DOMContentLoaded' : 'load';
   window.addEventListener(loadEvent, bootstrap);
 }
 
 })(window.CustomElements);
 
 (function() {
 // Patch to allow custom element and shadow dom to work together, from:
-// https://github.com/Polymer/platform/blob/master/src/patches-shadowdom-polyfill.js
+// https://github.com/Polymer/platform-dev/blob/60ece8c323c5d9325cbfdfd6e8cd180d4f38a3bc/src/patches-shadowdom-polyfill.js
 // include .host reference
 if (HTMLElement.prototype.createShadowRoot) {
   var originalCreateShadowRoot = HTMLElement.prototype.createShadowRoot;
   HTMLElement.prototype.createShadowRoot = function() {
     var root = originalCreateShadowRoot.call(this);
     root.host = this;
+    CustomElements.watchShadow(this);
     return root;
   }
 }
 
 
 // Patch to allow custom elements and shadow dom to work together, from:
 // https://github.com/Polymer/platform-dev/blob/2bb9c56d90f9ac19c2e65cdad368668aff514f14/src/patches-custom-elements.js
 if (window.ShadowDOMPolyfill) {
 
   // ensure wrapped inputs for these functions
@@ skipping 20 matching lines @@
 if (window.CustomElements && !CustomElements.useNative) {
   var originalImportNode = Document.prototype.importNode;
   Document.prototype.importNode = function(node, deep) {
     var imported = originalImportNode.call(this, node, deep);
     CustomElements.upgradeAll(imported);
     return imported;
   }
 }
 
 })();