Add top level app element

appengine/swarming/elements/imp/index/swarming-index.html

 <!--
   Copyright 2016 The LUCI Authors. All rights reserved.

[stephana, 2016/07/26 17:29:56]

Can you add a short explanation what the element does ?
If I understand it's the central container of everything 
on the index.html page that is not common. 

[kjlubick, 2016/07/26 19:23:36]

Done.

   Use of this source code is governed under the Apache License, Version 2.0
   that can be found in the LICENSE file.
 
   This in an HTML Import-able file that contains the definition
   of the following elements:
 
     <swarming-index>
 
   Usage:
 
     <swarming-index></swarming-index>
 
   Properties:
-    None.
+    None.  This is a top-level element.
 
   Methods:
     None.
 
   Events:
     None.
 -->
 
 <link rel="import" href="../../bower_components/polymer/polymer.html">
 <link rel="import" href="../../bower_components/iron-ajax/iron-ajax.html">
 
-<link rel="import" href="../common/auth-signin.html">
+<link rel="import" href="../common/swarming-app.html">
 
 <dom-module id="swarming-index">
   <template>
     <style>
       :host {
         display: block;
       }
     </style>
 
-    <h1>HELLO WORLD<h1>
+    <swarming-app
+      auth_headers="{{auth_headers}}"
+      name="Swarming"
+      busy="[[busy]]">
 
-    <!-- TODO(kjlubick) Remove this hard-coded client-id.-->
-    <auth-signin
-      auth-headers="{{auth}}"
-      client-id="20770472288-t5smpbpjptka4nd888fv0ctd23ftba2o.apps.googleusercontent.com"
-      on-auth-signin="signIn">
-    </auth-signin>
+      <iron-ajax id="request"
+        url="/_ah/api/swarming/v1/server/details"
+        headers="[[auth_headers]]"
+        handle-as="json"
+        last-response="{{serverDetails}}"
+        loading="{{busy}}">
+      </iron-ajax>
 
-    <iron-ajax id="request"
-      url="/_ah/api/swarming/v1/server/details"
-      headers="[[auth]]"
-      handle-as="json"
-      on-response="handleResponse">
-    </iron-ajax>
+      <h1>HELLO WORLD</h1>
+
+      <div>Server Version: [[serverDetails.server_version]]</div>
+
+    </swarming-app>
 
   </template>
   <script>
     Polymer({
       is: 'swarming-index',
 
+      properties: {
+        auth_headers: {
+          type: Object,
+          observer: "signIn",
+        },
+
+        serverDetails: {
+          type: String,
+        }
+      },
+
       signIn: function(){
         this.$.request.generateRequest();
       },
 
-      handleResponse: function(a,b){
-        console.log(this.$.request.lastResponse);
-      }
     });
   </script>
 </dom-module>