Make the buttons on task-page work

appengine/swarming/elements/res/imp/common/swarming-app.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-app>
 
@@ skipping 97 matching lines @@
           <div class="small right">
             Server:
             <a href$="[[_versionLink(server_version)]]">
               [[server_version.server_version]]
             </a>
           </div>
           <auth-signin
               class="right"
               client_id="[[client_id]]"
               auth_headers="{{auth_headers}}"
+              profile="{{profile}}"
               signed_in="{{signed_in}}">
           </auth-signin>
         </app-toolbar>
       </app-header>
       <div class="main-content">
         <content></content>
       </div>
         <a target="_blank" href="https://bugs.chromium.org/p/chromium/issues/entry?components=Infra%3EPlatform%3ESwarming&owner=kjlubick@chromium.org&status=Assigned">
           <paper-fab mini icon="icons:bug-report"></paper-fab>
         </a>
@@ skipping 27 matching lines @@
         },
 
         permissions: {
           type: Object,
           value: function() {
             // If we aren't logged in, default to no permissions.
             return {};
           },
           notify: true,
         },
+        profile: {
+          type: Object,
+          notify: true,
+        },
 
         server_version: {
           type: Object,
           notify: true,
         },
 
         signed_in: {
           type: Boolean,
           value: false,
           notify: true,
@@ skipping 113 matching lines @@
         border: none;
         line-height: 20px;
         vertical-align: middle;
       }
 
       select {
         overflow-y: auto;
       }
   </style>
 </dom-module>