Use constexpr TaskTraits constructor in chrome.

chrome/browser/chromeos/policy/system_log_uploader.cc

 // Copyright (c) 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/chromeos/policy/system_log_uploader.h"
 
 #include <map>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 78 matching lines @@
     scoped_refptr<base::SequencedTaskRunner> task_runner)
     : task_runner_(task_runner) {}
 
 SystemLogDelegate::~SystemLogDelegate() {}
 
 void SystemLogDelegate::LoadSystemLogs(
     const LogUploadCallback& upload_callback) {
   // Run ReadFiles() in the thread that interacts with the file system and
   // return system logs to |upload_callback| on the current thread.
   base::PostTaskWithTraitsAndReplyWithResult(
-      FROM_HERE, base::TaskTraits().MayBlock().WithPriority(
-                     base::TaskPriority::BACKGROUND),
+      FROM_HERE, {base::MayBlock(), base::TaskPriority::BACKGROUND},
       base::Bind(&ReadFiles), upload_callback);
 }
 
 std::unique_ptr<policy::UploadJob> SystemLogDelegate::CreateUploadJob(
     const GURL& upload_url,
     policy::UploadJob::Delegate* delegate) {
   chromeos::DeviceOAuth2TokenService* device_oauth2_token_service =
       chromeos::DeviceOAuth2TokenServiceFactory::Get();
 
   scoped_refptr<net::URLRequestContextGetter> system_request_context =
@@ skipping 215 matching lines @@
   // Ensure that we never have more than one pending delayed task
   // (InvalidateWeakPtrs() will cancel any pending log uploads).
   weak_factory_.InvalidateWeakPtrs();
   task_runner_->PostDelayedTask(FROM_HERE,
                                 base::Bind(&SystemLogUploader::StartLogUpload,
                                            weak_factory_.GetWeakPtr()),
                                 delay);
 }
 
 }  // namespace policy