Added base template for config ui.

appengine/config_service/ui/bower_components/webcomponentsjs/tests/imports/simple-element.html

+<!--
+@license
+Copyright (c) 2016 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
+-->
+
+<script>
+  // Kick off shady CSS.
+  var template = document.createElement('template');
+  template.innerHTML =
+    `
+      <style>:host {color: blue;} .red-text {color: red;} </style>
+      <p class="red-text">Shadow DOM</p>
+      <slot id="slot"></slot>
+    `;
+  if (template) {
+    if (window.ShadyCSS) {
+      window.ShadyCSS.prepareTemplate(template, 'simple-element');
+    }
+  }
+
+  class SimpleElement extends HTMLElement {
+    constructor() {
+      super();
+      this.bestName = 'batman';
+      if (window.ShadyCSS) {
+        window.ShadyCSS.styleElement(this);
+      }
+
+      if (template && !this.shadowRoot) {
+        this.attachShadow({mode: 'open'});
+        this.shadowRoot.appendChild(document.importNode(template.content, true));
+      }
+    }
+  }
+
+  window.customElements.define('simple-element', SimpleElement);
+</script>