Add server version to all pages

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

 <!--
   Copyright 2016 The LUCI Authors. All rights reserved.
   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>
 
@@ skipping 31 matching lines @@
         background-color: #f5f5f5;
         border: 1px solid #ccc;
         border-radius: 4px;
       }
     </style>
 
     <swarming-app
       client_id="[[client_id]]"
       auth_headers="{{auth_headers}}"
       permissions="{{_permissions}}"
+      server_version="{{_server_version}}"
       name="Swarming Server"
       busy="[[_busy]]">
 
       <h2>Service Status</h2>
-      <div>Server Version: [[serverDetails.server_version]]</div>
+      <div>Server Version: [[_server_version.server_version]]</div>
       <ul>
         <li>
           <!-- TODO(kjlubick) convert these linked pages to Polymer-->
           <a href="/stats">Usage statistics</a>
         </li>
         <li>
           <a href="/restricted/mapreduce/status">Map Reduce Jobs</a>
         </li>
         <li>
-          <a href$="[[_makeInstancesUrl(serverDetails,_project_id)]]">View version's instances on Cloud Console</a>
+          <a href$="[[_makeInstancesUrl(_server_version,_project_id)]]">View version's instances on Cloud Console</a>
         </li>
         <li>
           <a><a href$="[[_makeErrorUrl(_project_id)]]">View server errors on Cloud Console</a></a>
         </li>
         <li>
           <a><a href$="[[_makeLogUrl(_project_id)]]">View logs for HTTP 5xx on Cloud Console</a></a>
         </li>
       </ul>
 
       <h2>Configuration</h2>
@@ skipping 47 matching lines @@
 
       behaviors: [
           SwarmingBehaviors.CommonBehavior,
       ],
 
       properties: {
         client_id: {
           type: String,
         },
 
-        auth_headers: {
-          type: Object,
-          observer: "signIn",
-        },
-
-        serverDetails: {
-          type: Object,
-        },
-
         _bootstrap_token: {
           type: String,
           // TODO(kjlubick): fetch this from an API
           value: "abc123",
         },
         _busy: {
           type: Boolean,
           value: false,
         },
         _host_url: {
           type: String,
           value: function() {
             return location.origin;
           },
         },
         _permissions: {
           type: Object,
         },
         _project_id: {
           type: String,
           value: function() {
             var idx = location.hostname.indexOf(".appspot.com");
             return location.hostname.substring(0, idx);
           },
-        }
+        },
+        _server_version: {
+          type: Object,
+        },
       },
 
-      signIn: function(){
-        this._getJsonAsync("serverDetails", "/_ah/api/swarming/v1/server/details",
-          "_busy", this.auth_headers);
-      },
 
       _cannotBootstrap: function(permissions) {
         return !(permissions && permissions.get_bootstrap_token);
       },
 
       _makeInstancesUrl: function(details, project_id) {
         return "https://console.cloud.google.com/appengine/instances?project="+
             project_id+"&versionId="+details.server_version;
       },
 
       _makeErrorUrl: function(project_id) {
         return "https://console.cloud.google.com/errors?project="+
             project_id;
       },
 
       _makeLogUrl: function(project_id) {
         return "https://pantheon.corp.google.com/logs/viewer?filters=text:status:500..599&project="+
             project_id;
       },
 
     });
   </script>
 </dom-module>