Make old version bots show up yellow on botlist

appengine/swarming/ui/res/imp/botlist/bot-list.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>
 
@@ skipping 27 matching lines @@
 <link rel="import" href="bot-list-shared-behavior.html">
 <link rel="import" href="bot-list-summary.html">
 
 <dom-module id="bot-list">
   <template>
     <style include="iron-flex iron-flex-alignment iron-positioning swarming-app-style dynamic-table-style">
       bot-filters, bot-list-summary {
         margin-bottom: 8px;
         margin-right: 10px;
       }
+      .old_version {
+        background-color: #ffffdd;
+      }
       .quarantined, .bad-device {
         background-color: #ffdddd;
       }
       .dead {
         background-color: #cccccc;
       }
       .alt {
         background-color: #f8f8f8;
       }
       .bot-list th > span {
@@ skipping 118 matching lines @@
             </tr>
           </thead>
           <tbody>
             <template
                 id="bot_table"
                 is="dom-repeat"
                 items="[[_filteredSortedItems]]"
                 as="bot"
                 initial-count=50>
 
-              <tr class$="[[_botClass(bot)]]">
+              <tr class$="[[_botClass(bot,_server_details.bot_version)]]">
                 <td>
                   <a
                       class="center"
                       href$="[[_botLink(bot.bot_id)]]"
                       target="_blank"
                       rel="noopener">
                       [[bot.bot_id]]
                   </a>
                 </td>
                 <td hidden$="[[_hide('cloud_console_link', _columns.*)]]">
@@ skipping 398 matching lines @@
         "_checkDeviceColumns(_columns.*)"
       ],
 
       _androidAliasDevice: function(device) {
         if (device.notReady) {
           return UNAUTHENTICATED.toUpperCase();
         }
         return swarming.alias.android(this._deviceType(device));
       },
 
-      _botClass: function(bot) {
+      _botClass: function(bot, serverVersion) {
+        var classes = "";
         if (bot.is_dead) {
-          return "dead";
+          classes += "dead ";
         }
         if (bot.quarantined) {
-          return "quarantined";
+          classes += "quarantined ";
         }
-        return "";
+        if (bot.version !== serverVersion) {
+          classes += "old_version";
+        }
+        return classes;
       },
 
       _ccLink: function(bot){
         var z = this._attribute(bot, "zone")[0];
         if (z === "unknown") {
           return undefined;
         }
         return this._cloudConsoleLink(z, bot.bot_id);
       },
 
@@ skipping 52 matching lines @@
           return;
         }
         var url = "/api/swarming/v1/bots/list?" + sk.query.fromParamSet(this._query_params);
         this.$.page_bots.load(url,this._auth_headers);
       }
 
     });
   })();
   </script>
 </dom-module>