Throw exceptions when attempts are made to use localStorage in packaged apps.

chrome/test/data/extensions/platform_apps/storage/test.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.
 
+function assertContains(string, substring, error) {
+  chrome.test.assertTrue(string.indexOf(substring) != -1, error);
+}
+
 chrome.test.runTests([
   function testOpenDatabase() {
     chrome.test.assertTrue(!window.openDatabase);
     chrome.test.succeed();
   },
 
   function testOpenDatabaseSync() {
     chrome.test.assertTrue(!window.openDatabaseSync);
     chrome.test.succeed();
   },
 
   function testLocalStorage() {
-    chrome.test.assertTrue(!window.localStorage);
-    chrome.test.succeed();
+    try {
+      window.localStorage;
+      chrome.test.fail('error not thrown');
+    } catch (e) {
+      var message = e.message || e;
+      var expected = 'is not available in packaged apps. ' +
+                     'Use chrome.storage.local instead.';
+      assertContains(message, expected, 'Unexpected message ' + message);
+      chrome.test.succeed();
+    }
   }
 ]);