Remove the rest of iron-ajax from bot-list-data

appengine/swarming/elements/res/imp/tasklist/task-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 22 matching lines @@
     tasks: Array<Object>, all tasks returned by the server.
 
   Methods:
     signIn(): Force a signin of the user using OAuth.  This happens
         automatically when auth_headers is set.
 
   Events:
     None.
 -->
 
-<link rel="import" href="/res/imp/bower_components/iron-ajax/iron-ajax.html">
 <link rel="import" href="/res/imp/common/common-behavior.html">
 
 <dom-module id="task-list-data">
   <script>
   (function(){
     Polymer({
       is: 'task-list-data',
 
       behaviors: [
           SwarmingBehaviors.CommonBehavior,
@@ skipping 163 matching lines @@
         pMap["deduped_from"] = [];
         pMap["duration"] = [];
         pMap["modified_ts"] = [];
         pMap["server_versions"] = [];
         pMap["started_ts"] = [];
 
         return pMap;
       },
 
       _request: function() {
-        // wait until the user has logged in before requesting this.
-        if (!this.auth_headers) {
+        // wait until the user has logged in and the filters have loaded before requesting this to avoid double or even triple requests.
+        if (!this.auth_headers || !this.query_params) {
           return;
         }
         this._getJsonAsync("_list", "/_ah/api/swarming/v1/tasks/list",
           "_busy1", this.auth_headers, this.query_params);
       },
 
       _tasks: function() {
         if (!this._list || !this._list.items) {
           return [];
         }
         // Do any preprocessing here
         this._list.items.forEach(function(t) {
           var tagMap = {};
           t.tags.forEach(function(tag) {
             var split = tag.split(":", 1)
             var key = split[0];
             var rest = tag.substring(key.length + 1);
             tagMap[key] = rest;
           });
           t.tagMap = tagMap;
         });
         return this._list.items;
       }
     });
   })();
   </script>
 </dom-module>