Added group policies to enable/disable importing of data from other browsers.

chrome/browser/resources/options/import_data_overlay.js

 // Copyright (c) 2011 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 OptionsPage = options.OptionsPage;
 
   /**
    * ImportDataOverlay class
    * Encapsulated handling of the 'Import Data' overlay page.
@@ skipping 70 matching lines @@
           $('import-history').checked || $('import-favorites').checked ||
           $('import-passwords').checked || $('import-search').checked;
       $('import-data-commit').disabled = !somethingToImport;
     },
 
     /**
      * Sets the sensitivity of all the checkboxes and the commit button.
      * @private
      */
     setControlsSensitive_: function(sensitive) {
-      var checkboxes =
-          document.querySelectorAll('#import-checkboxes input[type=checkbox]');
-      for (var i = 0; i < checkboxes.length; i++)
-        this.setUpCheckboxState_(checkboxes[i], sensitive);
+      var importOptions = ['history', 'favorites', 'passwords', 'search'];
+      for (var i = 0; i < importOptions.length; i++) {
+        var checkbox = $('import-' + importOptions[i]);
+        var enabled = !(checkbox.controlledBy == 'undefined') && sensitive;
+        this.setUpCheckboxState_(checkbox, enabled);
+      }
       $('import-data-commit').disabled = !sensitive;
     },
 
     /**
      * Set enabled and checked states a checkbox element.
      * @param {Object} checkbox A checkbox element.
      * @param {boolean} enabled The enabled state of the chekbox.
      * @private
      */
     setUpCheckboxState_: function(checkbox, enabled) {
       checkbox.disabled = !enabled;
-      checkbox.checked = enabled;
     },
 
     /**
      * Update the enabled and checked states of all checkboxes.
      * @private
      */
     updateCheckboxes_: function() {
       var index = $('import-browsers').selectedIndex;
       var browserProfile;
       if (this.browserProfiles.length > index)
         browserProfile = this.browserProfiles[index];
       var importOptions = ['history', 'favorites', 'passwords', 'search'];
       for (var i = 0; i < importOptions.length; i++) {
         var checkbox = $('import-' + importOptions[i]);
-        this.setUpCheckboxState_(checkbox,
-            browserProfile ? browserProfile[importOptions[i]] : false);
+        var enabled = (checkbox.controlledBy == 'undefined') &&
+                       (browserProfile ?
+                            browserProfile[importOptions[i]] : false);

[Mattias Nissler (ping if slow), 2011/07/20 09:28:31]

maybe break the line after the initial = and then the second line will maybe fit
without breaking after the ?

If you don't like this, then you need to fix alignment: one space less in 123
and 4 spaces indentation from 123 to 124

+        this.setUpCheckboxState_(checkbox, enabled);
       }
     },
 
     /**
      * Update the supported browsers popup with given entries.
      * @param {array} browsers List of supported browsers name.
      * @private
      */
     updateSupportedBrowsers_: function(browsers) {
       this.browserProfiles = browsers;
@@ skipping 12 matching lines @@
         for (var i = 0; i < browserCount; i++) {
           var browser = browsers[i]
           var option = new Option(browser['name'], browser['index']);
           browserSelect.appendChild(option);
         }
 
         this.updateCheckboxes_();
         this.validateCommitButton_();
       }
     },
+
+    /**
+    * Clear import prefs set when user checks/unchecks a checkbox so that the
+    * each checkbox goes back to the default "checked" state.
+    * @private
+    */
+    clearUserPrefs_: function() {
+       var importPrefs = ['import_history',
+                          'import_bookmarks',
+                          'import_saved_passwords',
+                          'import_search_engine'];
+       for (var i = 0; i < importPrefs.length; i++)
+          Preferences.clearPref(importPrefs[i], undefined);
+    },
+  };
+
+
+  ImportDataOverlay.clearUserPrefs = function() {
+    ImportDataOverlay.getInstance().clearUserPrefs_();
   };
 
   /**
    * Update the supported browsers popup with given entries.
    * @param {array} list of supported browsers name.
    */
   ImportDataOverlay.updateSupportedBrowsers = function(browsers) {
     ImportDataOverlay.getInstance().updateSupportedBrowsers_(browsers);
   };
 
@@ skipping 13 matching lines @@
     }
     $('import-browsers').disabled = state;
     $('import-throbber').style.visibility = state ? "visible" : "hidden";
     ImportDataOverlay.getInstance().validateCommitButton_();
   };
 
   /**
    * Remove the import overlay from display.
    */
   ImportDataOverlay.dismiss = function() {
+    ImportDataOverlay.clearUserPrefs();
     OptionsPage.closeOverlay();
   };
 
   /**
    * Show a message confirming the success of the import operation.
    */
   ImportDataOverlay.confirmSuccess = function() {
     var showBookmarksMessage = $('import-favorites').checked;
     ImportDataOverlay.setImportingState(false);
     $('import-data-configure').hidden = true;
     $('import-data-success').hidden = false;
     $('import-find-your-bookmarks').hidden = !showBookmarksMessage;
   };
 
   // Export
   return {
     ImportDataOverlay: ImportDataOverlay
   };
 });