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

chrome/test/data/extensions/api_test/automation/tests/desktop/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 findAutomationNode(root, condition) {
   if (condition(root))
     return root;
 
   var children = root.children();
   for (var i = 0; i < children.length; i++) {
     var result = findAutomationNode(children[i], condition);
     if (result)
       return result;
   }
   return null;
 }
 
 function setupAndRunTests(allTests) {
   chrome.automation.getDesktop(function(treeArg) {
     tree = treeArg;
     chrome.test.runTests(allTests);
   });
 }