Expose html attributes in automation tree.

chrome/test/data/extensions/api_test/automation/tests/tabs/attributes.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 ActiveDescendantAttribute = [ 'activeDescendant' ];
 var LinkAttributes = [ 'url' ];
 var DocumentAttributes = [ 'docUrl',
                            'docTitle',
                            'docLoaded',
                            'docLoadingProgress' ];
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                               DocumentAttributes,
                               ScrollableAttributes,
                               EditableTextAttributes,
                               RangeAttributes,
                               TableAttributes,
                               TableCellAttributes);
     for (var attributeAttr in allAttributes) {
       assertFalse(attributeAttr in div);
     }
     chrome.test.succeed();
+  },
+
+  function testHtmlAttributes() {
+    var editable = rootNode.find({ role: 'textField' });
+    assertTrue(editable !== undefined);
+    assertEq('text', editable.htmlAttributes.type);
+    chrome.test.succeed();
   }
 ];
 
 setUpAndRunTests(allTests, 'attributes.html');