Add command in to swarming 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 290 matching lines @@
                     </button>
                   </td>
                 </tr>
               </template>
               <template is="dom-if" if="[[_request_detail]]">
                 <tr>
                   <td>Extra Args</td>
                   <td class="code">[[_extraArgs(_request)]]</td>
                 </tr>
                 <tr>
+                  <td>Command</td>
+                  <td class="code">[[_command(_request)]]</td>
+                </tr>
+                <tr>
                   <td rowspan$="[[_rowspan(_request.tags)]]">Tags</td>
                 </tr>
                 <template is="dom-repeat" items="{{_request.tags}}" as="tag">
                   <tr>
                     <td>[[tag]]</td>
                   </tr>
                 </template>
 
                 <tr>
                   <td>Execution timeout</td>
@@ skipping 299 matching lines @@
           p.requested = p.package_name + ":" + p.version;
           actual.forEach(function(c) {
             if (c.path === p.path) {
               p.actual = c.package_name + ":" + c.version;
             }
           });
         });
         return packages;
       },
 
+      _command: function(request) {
+        if (!request || !request.properties) {
+          return "";
+        }
+        var args = request.properties.command || [];
+        return args.join(" ");
+      },
+
       _disambiguate: function(taskId, result) {
         if (!taskId.endsWith("0") || !result) {
           return false;
         }
         return result.try_number > 1;
       },
 
       _empty: function(array) {
         return !array || array.length == 0;
       },
@@ skipping 168 matching lines @@
         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>