[MAC] Disable 'Import' button when visible checkboxes are unchecked.

chrome/browser/resources/options/import_data_overlay.js

 // Copyright (c) 2012 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.
 
 cr.define('options', function() {
   var Page = cr.ui.pageManager.Page;
   var PageManager = cr.ui.pageManager.PageManager;
 
   /**
    * ImportDataOverlay class
    * Encapsulated handling of the 'Import Data' overlay page.
    * @class
    */
   function ImportDataOverlay() {
     Page.call(this,
               'importData',
               loadTimeData.getString('importDataOverlayTabTitle'),
               'import-data-overlay');
   }
 
   cr.addSingletonGetter(ImportDataOverlay);
 
+  /**
+  * @param {string} type The type of data to import. Used in the element's ID.
+  */
+  function importable(type) {
+    var id = 'import-' + type;
+    return $(id).checked && !$(id + '-with-label').hidden;
+  }
+
   ImportDataOverlay.prototype = {
     // Inherit from Page.
     __proto__: Page.prototype,
 
     /** @override */
     initializePage: function() {
       Page.prototype.initializePage.call(this);
 
       var self = this;
       var checkboxes =
@@ skipping 35 matching lines @@
       // Form controls are disabled until the profile list has been loaded.
       self.setAllControlsEnabled_(false);
     },
 
     /**
      * Sets the enabled and checked state of the commit button.
      * @private
      */
     validateCommitButton_: function() {
       var somethingToImport =
-          $('import-history').checked || $('import-favorites').checked ||
-          $('import-passwords').checked || $('import-search').checked ||
-          $('import-autofill-form-data').checked;
+          importable('history') || importable('favorites') ||
+          importable('passwords') || importable('search') ||
+          importable('autofill-form-data');
       $('import-data-commit').disabled = !somethingToImport;
       $('import-choose-file').disabled = !$('import-favorites').checked;
     },
 
     /**
      * Sets the enabled state of all the checkboxes and the commit button.
      * @private
      */
     setAllControlsEnabled_: function(enabled) {
       var checkboxes =
@@ skipping 30 matching lines @@
 
       var browserProfile;
       if (this.browserProfiles.length > index)
         browserProfile = this.browserProfiles[index];
       var importOptions = ['history',
                            'favorites',
                            'passwords',
                            'search',
                            'autofill-form-data'];
       for (var i = 0; i < importOptions.length; i++) {
-        var checkbox = $('import-' + importOptions[i]);
+        var id = 'import-' + importOptions[i];
         var enable = browserProfile && browserProfile[importOptions[i]];
-        this.setUpCheckboxState_(checkbox, enable);
-        var checkboxWithLabel = $('import-' + importOptions[i] + '-with-label');
-        checkboxWithLabel.style.display = enable ? '' : 'none';
+        this.setUpCheckboxState_($(id), enable);
+        $(id + '-with-label').hidden = !enable;
       }
     },
 
     /**
      * Show or hide gray message at the bottom.
      * @private
      */
     updateBottomBar_: function() {
       var index = $('import-browsers').selectedIndex;
       var browserProfile;
@@ skipping 124 matching lines @@
     ImportDataOverlay.getInstance().validateCommitButton_();
 
     PageManager.showPageByName('importData');
   };
 
   // Export
   return {
     ImportDataOverlay: ImportDataOverlay
   };
 });