Gallery: replace paper-input of rename field with HTMLInputElement.

ui/file_manager/gallery/js/test_util.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.
 
 /**
  * This variable is checked in SelectFileDialogExtensionBrowserTest.
  * @type {number}
  */
 window.JSErrorCount = 0;
 
@@ skipping 47 matching lines @@
   chrome.test.assertTrue(element.dispatchEvent(new Event('change')));
 };
 
 /**
  * Changes the file name.
  *
  * @param {Window} contentWindow Window to be tested.
  * @param {string} newName Name to be newly assigned.
  */
 test.util.sync.changeName = function(contentWindow, newName) {
-  var nameBox = contentWindow.document.querySelector(
-      '.filename-spacer > paper-input');
-  // For paper-input, we need to focus on input element inside the component.
-  nameBox.inputElement.focus();
+  var nameBox = contentWindow.document.querySelector('.filename-spacer input');
+  nameBox.focus();
   nameBox.value = newName;
-  nameBox.inputElement.blur();
+  nameBox.blur();
 };
 
 // Register the test utils.
 test.util.registerRemoteTestUtils();