Use constexpr TaskTraits constructor in chrome.

chrome/browser/service_process/service_process_control.cc

 // Copyright (c) 2012 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/service_process/service_process_control.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 55 matching lines @@
   if (channel_.get()) {
     RunConnectDoneTasks();
     return;
   }
 
   // Actually going to connect.
   DVLOG(1) << "Connecting to Service Process IPC Server";
 
   mojo::MessagePipe pipe;
   base::PostTaskWithTraits(
-      FROM_HERE, base::TaskTraits().MayBlock().WithPriority(
-                     base::TaskPriority::BACKGROUND),
+      FROM_HERE, {base::MayBlock(), base::TaskPriority::BACKGROUND},
       base::Bind(&ConnectAsync, base::Passed(&pipe.handle1),
                  GetServiceProcessChannel()));
   // TODO(hclam): Handle error connecting to channel.
   auto io_task_runner =
       BrowserThread::GetTaskRunnerForThread(BrowserThread::IO);
   SetChannel(
       IPC::ChannelProxy::Create(IPC::ChannelMojo::CreateClientFactory(
                                     std::move(pipe.handle0), io_task_runner),
                                 this, io_task_runner));
 }
@@ skipping 323 matching lines @@
   if (process_.IsValid()) {
     BrowserThread::PostTask(
         BrowserThread::IO, FROM_HERE,
         base::Bind(&Launcher::DoDetectLaunched, this));
   } else {
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE, base::Bind(&Launcher::Notify, this));
   }
 }
 #endif  // !OS_MACOSX