Implement AutomationNode.querySelector().

chrome/test/data/extensions/api_test/automation/tests/tabs/tab_id.js

+
 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 function createBackgroundTab(url, callback) {
   chrome.tabs.query({ active: true }, function(tabs) {
     chrome.test.assertEq(1, tabs.length);
     var originalActiveTab = tabs[0];
     createTab(url, function(tab) {
       chrome.tabs.update(originalActiveTab.id, { active: true }, function() {
         callback(tab);
       });
     })
   });
 }
 
 function assertCorrectTab(rootNode) {
   var title = rootNode.attributes.docTitle;
   chrome.test.assertEq('Automation Tests', title);
   chrome.test.succeed();
 }
 
 var allTests = [
   function testGetTabById() {
-    getUrlFromConfig(function(url) {
+    getUrlFromConfig('index.html', function(url) {
       // Keep the NTP as the active tab so that we know we're requesting the
       // tab by ID rather than just getting the active tab still.
       createBackgroundTab(url, function(tab) {
         chrome.automation.getTree(tab.id, function(rootNode) {
           if (rootNode.attributes.docLoaded) {
             assertCorrectTab(rootNode);
             return;
           }
 
           rootNode.addEventListener('loadComplete', function() {
             assertCorrectTab(rootNode);
           });
         })
       });
     });
   }
 ];
 
 chrome.test.runTests(allTests);