Fix build error with gcc 4.8.2 about WARN_UNUSED_RESULT

chrome/browser/search/suggestions/suggestions_service_factory.cc

 // Copyright 2014 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/search/suggestions/suggestions_service_factory.h"
 
 #include <utility>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/prefs/pref_service.h"
@@ skipping 39 matching lines @@
   DependsOn(SigninManagerFactory::GetInstance());
   DependsOn(ProfileOAuth2TokenServiceFactory::GetInstance());
 }
 
 SuggestionsServiceFactory::~SuggestionsServiceFactory() {}
 
 KeyedService* SuggestionsServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* profile) const {
   scoped_refptr<base::SequencedTaskRunner> background_task_runner =
       BrowserThread::GetBlockingPool()->GetSequencedTaskRunner(
-          BrowserThread::GetBlockingPool()->GetSequenceToken());
+          base::SequencedWorkerPool::GetSequenceToken());
 
   Profile* the_profile = static_cast<Profile*>(profile);
 
   SigninManagerBase* signin_manager =
       SigninManagerFactory::GetForProfile(the_profile);
   ProfileOAuth2TokenService* token_service =
       ProfileOAuth2TokenServiceFactory::GetForProfile(the_profile);
 
   scoped_ptr<SuggestionsStore> suggestions_store(
       new SuggestionsStore(the_profile->GetPrefs()));
@@ skipping 17 matching lines @@
       std::move(suggestions_store), std::move(thumbnail_manager),
       std::move(blacklist_store));
 }
 
 void SuggestionsServiceFactory::RegisterProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry) {
   SuggestionsService::RegisterProfilePrefs(registry);
 }
 
 }  // namespace suggestions