Use constexpr TaskTraits constructor in chrome.

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 <memory>
 #include <utility>
 
 #include "base/memory/ptr_util.h"
@@ skipping 46 matching lines @@
   DependsOn(ProfileOAuth2TokenServiceFactory::GetInstance());
   DependsOn(ProfileSyncServiceFactory::GetInstance());
 }
 
 SuggestionsServiceFactory::~SuggestionsServiceFactory() {}
 
 KeyedService* SuggestionsServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   scoped_refptr<base::SequencedTaskRunner> background_task_runner =
       base::CreateSequencedTaskRunnerWithTraits(
-          base::TaskTraits().MayBlock().WithPriority(
-              base::TaskPriority::BACKGROUND));
+          {base::MayBlock(), base::TaskPriority::BACKGROUND});
 
   Profile* profile = static_cast<Profile*>(context);
 
   SigninManagerBase* signin_manager =
       SigninManagerFactory::GetForProfile(profile);
   ProfileOAuth2TokenService* token_service =
       ProfileOAuth2TokenServiceFactory::GetForProfile(profile);
   browser_sync::ProfileSyncService* sync_service =
       ProfileSyncServiceFactory::GetForProfile(profile);
 
@@ skipping 20 matching lines @@
       std::move(suggestions_store), std::move(thumbnail_manager),
       std::move(blacklist_store));
 }
 
 void SuggestionsServiceFactory::RegisterProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry) {
   SuggestionsServiceImpl::RegisterProfilePrefs(registry);
 }
 
 }  // namespace suggestions