Added base template for config ui.

appengine/config_service/ui/bower_components/polymer/lib/elements/custom-style.html

+<!--
+@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
+-->
+<link rel="import" href="../../../shadycss/custom-style-interface.html">
+<link rel="import" href="../utils/style-gather.html">
+<script>
+(function() {
+  'use strict';
+
+  const attr = 'include';
+
+  const CustomStyleInterface = window.ShadyCSS.CustomStyleInterface;
+
+  /**
+   * Custom element for defining styles in the main document that can take
+   * advantage of several special features of Polymer's styling system:
+   *
+   * - Document styles defined in a custom-style are shimmed to ensure they
+   *   do not leak into local DOM when running on browsers without native
+   *   Shadow DOM.
+   * - Custom properties used by Polymer's shim for cross-scope styling may
+   *   be defined in an custom-style. Use the :root selector to define custom
+   *   properties that apply to all custom elements.
+   *
+   * To use, simply wrap an inline `<style>` tag in the main document whose
+   * CSS uses these features with a `<custom-style>` element.
+   *
+   * @extends HTMLElement
+   * @memberof Polymer
+   * @summary Custom element for defining styles in the main document that can
+   *   take advantage of Polymer's style scoping and custom properties shims.
+   */
+  class CustomStyle extends HTMLElement {
+    constructor() {
+      super();
+      this._style = null;
+      CustomStyleInterface.addCustomStyle(this);
+    }
+    /**
+     * Returns the light-DOM `<style>` child this element wraps.  Upon first
+     * call any style modules referenced via the `include` attribute will be
+     * concatenated to this element's `<style>`.
+     *
+     * @return {HTMLStyleElement} This element's light-DOM `<style>`
+     */
+    getStyle() {
+      if (this._style) {
+        return this._style;
+      }
+      const style = this.querySelector('style');
+      if (!style) {
+        return;
+      }
+      this._style = style;
+      const include = style.getAttribute(attr);
+      if (include) {
+        style.removeAttribute(attr);
+        style.textContent = Polymer.StyleGather.cssFromModules(include) + style.textContent;
+      }
+      return this._style;
+    }
+  }
+
+  window.customElements.define('custom-style', CustomStyle);
+  Polymer.CustomStyle = CustomStyle;
+})();
+</script>