Take the Extension Storage API out of experimental.

chrome/common/extensions/docs/examples/api/storage/stylizr/options.js

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
 // Store settings in the synchronized repository.
-var storage = chrome.experimental.storage.sync;
+var storage = chrome.storage.sync;
 
 // Get at the DOM controls used in the sample.
 var resetButton = document.querySelector('button.reset');
 var submitButton = document.querySelector('button.submit');
 var textarea = document.querySelector('textarea');
 
 // Load any CSS that may have previously been saved.
 loadChanges();
 
 submitButton.addEventListener('click', saveChanges);
 resetButton.addEventListener('click', reset);
 
 function saveChanges() {
   // Get the current CSS snippet from the form.
   var cssCode = textarea.value;
   // Check that there's some code there.
   if (!cssCode) {
     message('Error: No CSS specified');
     return;
   }
-  // Save it locally (un-synchronized) using the Chrome extension storage API.
+  // Save it using the Chrome extension storage API.
   storage.set({'css': cssCode}, function() {
     // Notify that we saved.
     message('Settings saved');
   });
 }
 
 function loadChanges() {
   storage.get('css', function(items) {
     if (items.css) {
       textarea.value = items.css;
@@ skipping 11 matching lines @@
   textarea.value = '';
 }
 
 function message(msg) {
   var message = document.querySelector('.message');
   message.innerText = msg;
   setTimeout(function() {
     message.innerText = '';
   }, 3000);
 }