Use constexpr TaskTraits constructor in chrome.

chrome/browser/android/offline_pages/offline_page_model_factory.cc

 // Copyright 2015 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/android/offline_pages/offline_page_model_factory.h"
 
 #include <utility>
 
 #include "base/files/file_path.h"
 #include "base/memory/singleton.h"
@@ skipping 23 matching lines @@
 OfflinePageModel* OfflinePageModelFactory::GetForBrowserContext(
     content::BrowserContext* context) {
   return static_cast<OfflinePageModelImpl*>(
       GetInstance()->GetServiceForBrowserContext(context, true));
 }
 
 KeyedService* OfflinePageModelFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   Profile* profile = Profile::FromBrowserContext(context);
   scoped_refptr<base::SequencedTaskRunner> background_task_runner =
-      base::CreateSequencedTaskRunnerWithTraits(base::TaskTraits().MayBlock());
+      base::CreateSequencedTaskRunnerWithTraits({base::MayBlock()});
 
   base::FilePath store_path =
       profile->GetPath().Append(chrome::kOfflinePageMetadataDirname);
   std::unique_ptr<OfflinePageMetadataStore> metadata_store(
       new OfflinePageMetadataStoreSQL(background_task_runner, store_path));
 
   base::FilePath archives_dir =
       profile->GetPath().Append(chrome::kOfflinePageArchivesDirname);
 
   return new OfflinePageModelImpl(std::move(metadata_store), archives_dir,
                                   background_task_runner);
 }
 
 }  // namespace offline_pages