Create a secondary file thread, FILE_USER_BLOCKING...

chrome/browser/extensions/extension_service_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 "chrome/browser/extensions/extension_service_unittest.h"
 
 #include <algorithm>
 #include <set>
 #include <vector>
 
@@ skipping 368 matching lines @@
 
 // Our message loop may be used in tests which require it to be an IO loop.
 ExtensionServiceTestBase::ExtensionServiceTestBase()
     : loop_(MessageLoop::TYPE_IO),
       service_(NULL),
       expected_extensions_count_(0),
       ui_thread_(BrowserThread::UI, &loop_),
       db_thread_(BrowserThread::DB, &loop_),
       webkit_thread_(BrowserThread::WEBKIT, &loop_),
       file_thread_(BrowserThread::FILE, &loop_),
+      file_user_blocking_thread_(BrowserThread::FILE_USER_BLOCKING, &loop_),
       io_thread_(BrowserThread::IO, &loop_) {
   FilePath test_data_dir;
   if (!PathService::Get(chrome::DIR_TEST_DATA, &test_data_dir)) {
     ADD_FAILURE();
     return;
   }
   data_dir_ = test_data_dir.AppendASCII("extensions");
 }
 
 ExtensionServiceTestBase::~ExtensionServiceTestBase() {
@@ skipping 3897 matching lines @@
   ASSERT_FALSE(AddPendingSyncInstall());
 
   // Wait for the external source to install.
   WaitForCrxInstall(crx_path_, INSTALL_NEW);
   ASSERT_TRUE(IsCrxInstalled());
 
   // Now that the extension is installed, sync request should fail
   // because the extension is already installed.
   ASSERT_FALSE(AddPendingSyncInstall());
 }