Add human readable programmatic enum name/values to chrome.automation.

chrome/test/data/extensions/api_test/automation/tests/tabs/common.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.
 
 var assertEq = chrome.test.assertEq;
 var assertFalse = chrome.test.assertFalse;
 var assertTrue = chrome.test.assertTrue;
 
+var EventType = chrome.automation.EventType;
+var RoleType = chrome.automation.RoleType;
+var StateType = chrome.automation.StateType;
+
 var tree = null;
 
 function setUpAndRunTests(allTests) {
   chrome.test.getConfig(function(config) {
     assertTrue('testServer' in config, 'Expected testServer in config');
     var url = 'http://a.com:PORT/index.html'
         .replace(/PORT/, config.testServer.port);
 
     function gotTree(returnedTree) {
       tree = returnedTree;
       tree.addEventListener('loadComplete', function() {
         chrome.test.runTests(allTests);
       });
     }
     chrome.tabs.create({ 'url': url }, function() {
       chrome.automation.getTree(gotTree);
     });
   });
 }
-