Create a new URLRequestJobFactory for isolated request contexts.

chrome/test/data/extensions/api_test/xhr_persistent_fs/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.
+
+function createFile() {
+  webkitRequestFileSystem(window.PERSISTENT, 1024, gotFS, fail);
+};
+
+function gotFS(fs) {
+  fs.root.getFile("hoge", {create: true, exclusive: false}, gotFileEntry, fail);
+}
+
+function gotFileEntry(entry) {
+  entry.createWriter(gotWriter.bind(null, entry), fail);
+}
+
+function gotWriter(entry, writer) {
+  writer.write(new Blob(["fuga"]));
+  writer.onwrite = didWrite.bind(null, entry);
+  writer.onerror = fail;
+}
+
+function didWrite(entry) {
+  var xhr = new XMLHttpRequest();
+  xhr.open("GET", entry.toURL());
+  xhr.send();
+  xhr.onload = pass;
+  xhr.onerror = fail;
+}
+
+function pass() {
+  if (window.chrome && chrome.test && chrome.test.succeed)
+    chrome.test.succeed();
+  document.body.innerText = "PASS";
+}
+
+function fail() {
+  if (window.chrome && chrome.test && chrome.test.fail)
+    chrome.test.fail();
+  document.body.innerText = "FAIL";
+}
+
+createFile();