Have content/ create and destroy its own threads.

chrome/browser/extensions/app_notification_storage_unittest.cc

 // Copyright (c) 2011 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.
 
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/message_loop.h"
 #include "base/path_service.h"
 #include "base/scoped_temp_dir.h"
 #include "base/stl_util.h"
 #include "chrome/browser/extensions/app_notification.h"
 #include "chrome/browser/extensions/app_notification_storage.h"
 #include "chrome/browser/extensions/app_notification_test_util.h"
 #include "chrome/common/extensions/extension_test_util.h"
 #include "content/test/test_browser_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 111 matching lines @@
   util::AddNotifications(&list1, id, 5, "one");
   util::AddNotifications(&list2, id, 7, "two");
 
   // Put list1 in, then replace with list2 and verify we get list2 back.
   EXPECT_TRUE(storage_->Set(id, list1));
   EXPECT_TRUE(storage_->Set(id, list2));
   AppNotificationList tmp_list;
   EXPECT_TRUE(storage_->Get(id, &tmp_list));
   util::ExpectListsEqual(list2, tmp_list);
 }