Fix Swarming UI timezone bug

appengine/swarming/ui/res/imp/botlist/bot-list-data.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:
 
     <bot-list-data>
 
@@ skipping 42 matching lines @@
 
 <link rel="import" href="bot-list-shared-behavior.html">
 
 <dom-module id="bot-list-data">
 
   <script>
   (function(){
     var AVAILABLE = "available";
     var BLACKLIST_DIMENSIONS = ["quarantined", "error"];
 
+    var BOT_TIMES = ["first_seen_ts", "last_seen_ts", "lease_expiration_ts"];
+
     function aggregateTemps(temps) {
       if (!temps) {
         return {};
       }
       var zones = [];
       var avg = 0;
       for (k in temps) {
         zones.push(k +": "+temps[k]);
         avg += temps[k];
       }
@@ skipping 126 matching lines @@
             // still have devices in their state (the last known device attached)
             // but don't have the device_type dimension. In that case, we punt
             // on device type.
             var types = this._dimension(bot, "device_type") || ["unknown"];
             o.device_type = types[0];
             o.temp = aggregateTemps(o.temp);
             devices.push(o);
           }
           bot.state.devices = devices;
 
-          if (bot.last_seen_ts) {
-            bot.last_seen_ts = new Date(bot.last_seen_ts);
-          }
-          if (bot.first_seen_ts) {
-            bot.first_seen_ts = new Date(bot.first_seen_ts);
-          }
-          if (bot.lease_expiration_ts) {
-            bot.lease_expiration_ts = new Date(bot.lease_expiration_ts);
-          }
+          BOT_TIMES.forEach(function(time) {
+            swarming.sanitizeAndHumanizeTime(bot, time);
+          });
 
         }.bind(this));
         return json.items;
       },
 
       _fleet: function() {
         if (!this._count) {
           return {};
         }
         return {
@@ skipping 59 matching lines @@
 
         // No need to sort any of this, bot-filters sorts secondary items
         // automatically, especially when the user types a query.
         return pMap;
       },
 
     });
   })();
   </script>
 </dom-module>