Have content/ create and destroy its own threads.

chrome/browser/download/download_manager_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 <set>
 #include <string>
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/i18n/number_formatting.h"
 #include "base/i18n/rtl.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/message_loop.h"
 #include "base/stl_util.h"
 #include "base/string16.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "chrome/browser/download/chrome_download_manager_delegate.h"
 #include "chrome/browser/download/download_item_model.h"
 #include "chrome/browser/download/download_prefs.h"
 #include "chrome/browser/download/download_util.h"
 #include "chrome/browser/prefs/pref_service.h"
@@ skipping 861 matching lines @@
   EXPECT_FALSE(observer->hit_state(DownloadItem::REMOVING));
   EXPECT_TRUE(observer->was_updated());
   EXPECT_FALSE(observer->was_opened());
   EXPECT_TRUE(download->file_externally_removed());
   EXPECT_EQ(DownloadItem::COMPLETE, download->state());
   EXPECT_EQ(download_item_model->GetStatusText(),
             l10n_util::GetStringUTF16(IDS_DOWNLOAD_STATUS_REMOVED));
 
   EXPECT_FALSE(file_util::PathExists(new_path));
 }