Added base template for config ui.

appengine/config_service/ui/bower_components/shadycss/src/style-placeholder.js

+/**
+@license
+Copyright (c) 2017 The Polymer Project Authors. All rights reserved.
+This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
+The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
+The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
+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
+*/
+
+'use strict';
+
+import {applyStylePlaceHolder} from './style-util.js'
+import {nativeShadow} from './style-settings.js'
+
+/** @type {Object<string, !Node>} */
+let placeholderMap = {};
+
+/**
+ * @const {CustomElementRegistry}
+ */
+const ce = window['customElements'];
+if (ce && !nativeShadow) {
+  /**
+   * @const {function(this:CustomElementRegistry, string,function(new:HTMLElement),{extends: string}=)}
+   */
+  const origDefine = ce['define'];
+  /**
+   * @param {string} name
+   * @param {function(new:HTMLElement)} clazz
+   * @param {{extends: string}=} options
+   * @return {function(new:HTMLElement)}
+   */
+  const wrappedDefine = (name, clazz, options) => {
+    placeholderMap[name] = applyStylePlaceHolder(name);
+    return origDefine.call(/** @type {!CustomElementRegistry} */(ce), name, clazz, options);
+  }
+  ce['define'] = wrappedDefine;
+}
+
+export default placeholderMap;