Make platform apps get isolated storage by default.

chrome/test/data/extensions/platform_apps/isolation/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.
+
+chrome.test.getConfig(function(config) {
+  chrome.test.runTests([
+    function testCookieNotSet() {
+      var xhr = new XMLHttpRequest();
+      xhr.open(
+          'GET',
+          'http://localhost:' + config.testServer.port + '/echoheader?Cookie',
+          true);
+      xhr.onload = function() {
+        // Cookies should not have been passed in the request, so the echo of
+        // their header should be the Pythonic "None".
+        chrome.test.assertEq('None', xhr.responseText);
+        chrome.test.succeed();
+      };
+      xhr.onerror = function() {
+        chrome.test.fail('Unexpected HTTP status ' + xhr.status);
+      }
+      xhr.send();
+    }
+  ]);
+});