BlockingPool is flushed in DeviceOAuth2TokenServiceTest to prevent memory leaks.

chrome/browser/chromeos/settings/device_oauth2_token_service_unittest.cc

 // Copyright 2013 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/chromeos/settings/device_oauth2_token_service.h"
 
 #include "base/message_loop/message_loop.h"
 #include "base/prefs/testing_pref_service.h"
 #include "base/run_loop.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/chromeos/policy/device_policy_builder.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 #include "chrome/browser/chromeos/settings/device_settings_service.h"
 #include "chrome/browser/chromeos/settings/device_settings_test_helper.h"
 #include "chrome/browser/chromeos/settings/token_encryptor.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/test/base/scoped_testing_local_state.h"
 #include "chrome/test/base/testing_browser_process.h"
 #include "chromeos/cryptohome/system_salt_getter.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
@@ skipping 70 matching lines @@
         *device_policy_.GetSigningKey());
     DeviceSettingsService::Get()->SetSessionManager(
         &device_settings_test_helper_, owner_key_util_);
 
     CrosSettings::Initialize();
   }
 
   virtual void TearDown() OVERRIDE {
     CrosSettings::Shutdown();
     TestingBrowserProcess::GetGlobal()->SetBrowserPolicyConnector(NULL);
+    content::BrowserThread::GetBlockingPool()->FlushForTesting();
     DeviceSettingsService::Get()->UnsetSessionManager();
     DeviceSettingsService::Shutdown();
     SystemSaltGetter::Shutdown();
     DBusThreadManager::Shutdown();
     base::RunLoop().RunUntilIdle();
   }
 
   void CreateService() {
     oauth2_service_.reset(new DeviceOAuth2TokenService(
         request_context_getter_.get(), scoped_testing_local_state_.Get()));
@@ skipping 312 matching lines @@
 
   AssertConsumerTokensAndErrors(0, 1);
 
   // Retry should succeed.
   request = StartTokenRequest();
   PerformURLFetches();
   AssertConsumerTokensAndErrors(1, 1);
 }
 
 }  // namespace chromeos