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

chrome/test/data/extensions/api_test/automation/tests/tabs/sanity_check.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.
 
 // Do not test orientation or hover attributes (similar to exclusions on native
 // accessibility), since they can be inconsistent depending on the environment.
 var RemoveUntestedStates = function(state) {
-  delete state['horizontal'];
-  delete state['hovered'];
-  delete state['vertical'];
+  delete state[StateType.horizontal];
+  delete state[StateType.hovered];
+  delete state[StateType.vertical];
 };
 
 var allTests = [
   function testSimplePage() {
-    var title = tree.root.attributes['docTitle'];
+    var title = tree.root.attributes.docTitle;
     assertEq('Automation Tests', title);
     RemoveUntestedStates(tree.root.state);
     assertEq(
       {enabled: true, focusable: true, readOnly: true},
       tree.root.state);
     var children = tree.root.children();
     assertEq(1, children.length);
 
     var body = children[0];
-    assertEq('body', body.attributes['htmlTag']);
+    assertEq('body', body.attributes.htmlTag);
 
     RemoveUntestedStates(body.state);
     assertEq({enabled: true, readOnly: true},
              body.state);
 
     var contentChildren = body.children();
     assertEq(3, contentChildren.length);
     var okButton = contentChildren[0];
-    assertEq('Ok', okButton.attributes['name']);
+    assertEq('Ok', okButton.attributes.name);
     RemoveUntestedStates(okButton.state);
     assertEq({enabled: true, focusable: true, readOnly: true},
              okButton.state);
     var userNameInput = contentChildren[1];
     assertEq('Username',
-             userNameInput.attributes['description']);
+             userNameInput.attributes.description);
     RemoveUntestedStates(userNameInput.state);
     assertEq({enabled: true, focusable: true},
              userNameInput.state);
     var cancelButton = contentChildren[2];
     assertEq('Cancel',
-             cancelButton.attributes['name']);
+             cancelButton.attributes.name);
     RemoveUntestedStates(cancelButton.state);
     assertEq({enabled: true, focusable: true, readOnly: true},
              cancelButton.state);
 
     // Traversal.
     assertEq(undefined, tree.root.parent());
     assertEq(tree.root, body.parent());
 
     assertEq(body, tree.root.firstChild());
     assertEq(body, tree.root.lastChild());
@@ skipping 14 matching lines @@
     assertEq(cancelButton, userNameInput.nextSibling());
 
     assertEq(userNameInput, cancelButton.previousSibling());
     assertEq(undefined, cancelButton.nextSibling());
 
     chrome.test.succeed();
   }
 ];
 
 setUpAndRunTests(allTests);