Include expected outputs in Polymer UI

appengine/swarming/ui/res/imp/taskpage/task-page.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:
 
     <task-page>
 
@@ skipping 234 matching lines @@
                 </tr>
               </template>
               <tr>
                 <td>Isolated Inputs</td>
                 <td>
                   <a href$="[[_isolateLink(_request.properties.inputs_ref)]]">
                     [[_request.properties.inputs_ref.isolated]]
                   </a>
                 </td>
               </tr>
+              <template is="dom-if" if="[[_request.properties.outputs.length]]">
+                <tr>
+                  <td rowspan$="[[_rowspan(_request.properties.outputs)]]">Expected outputs</td>
+                </tr>
+                <template is="dom-repeat" items="{{_request.properties.outputs}}" as="output">
+                  <tr>
+                    <td>[[output]]</td>
+                  </tr>
+                </template>
+              </template>
               <template is="dom-if" if="[[_not(_request_detail)]]">
                 <tr>
                   <td>More Details</td>
                   <td>
                     <button on-click="_toggleDetails">
                       <iron-icon icon="icons:add-circle-outline"></iron-icon>
                     </button>
                   </td>
                 </tr>
               </template>
@@ skipping 441 matching lines @@
           }
         );
       },
 
       _rowspan: function(dims) {
         dims = dims || [];
         return dims.length + 1;
       },
 
       _empty: function(array) {
-        return array.length == 0;
+        return !array || array.length == 0;
       },
 
       _supportsMilo: function(request, showRaw) {
         return !showRaw && request && this._tag(request, "allow_milo");
       },
 
       _state: function(result) {
         if (!result) {
           return "";
         }
@@ skipping 27 matching lines @@
       _wasPickedUp: function(result) {
         return result && result.state !== this.PENDING && result.state !== this.CANCELED && result.state != this.EXPIRED;
       },
 
       _wasNotPickedUp: function(result) {
         return result && !this._wasPickedUp(result);
       },
     });
   })();
   </script>
-</dom-module>
+</dom-module>