Add sanbdoxed_pages to allow extension/app pages to be served in a sandboxed, unique origin

chrome/test/data/extensions/api_test/sandboxed_pages/main.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.
+
+var secret = 'main_window_secret';
+
+onmessage = function(event) {
+  var sandboxedWindow = event.source;
+  // They can't read our secret.
+  chrome.test.assertEq(undefined, event.data);
+
+  // And we can't read theirs.
+  chrome.test.assertEq(undefined, sandboxedWindow.secret);
+
+  chrome.test.succeed();
+};
+
+onload = function() {
+  chrome.test.runTests([
+    function sandboxedWindow() {
+      var w = window.open('sandboxed.html');
+    },
+
+    function sandboxedFrame() {
+      var iframe = document.createElement('iframe');
+      iframe.src = 'sandboxed.html';
+      document.body.appendChild(iframe);
+    }
+  ]);
+};