Use constexpr TaskTraits constructor in ui.

ui/ozone/platform/drm/host/drm_display_host_manager.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 "ui/ozone/platform/drm/host/drm_display_host_manager.h"
 
 #include <fcntl.h>
 #include <stddef.h>
 #include <xf86drm.h>
 
@@ skipping 230 matching lines @@
   while (!event_queue_.empty() && !task_pending_) {
     DisplayEvent event = event_queue_.front();
     event_queue_.pop();
     VLOG(1) << "Got display event " << kDisplayActionString[event.action_type]
             << " for " << event.path.value();
     switch (event.action_type) {
       case DeviceEvent::ADD:
         if (drm_devices_.find(event.path) == drm_devices_.end()) {
           base::PostTaskWithTraits(
               FROM_HERE,
-              base::TaskTraits()
-                  .WithShutdownBehavior(
-                      base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN)
-                  .MayBlock(),
+              {base::MayBlock(),
+               base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN},
               base::Bind(&OpenDeviceAsync, event.path,
                          base::ThreadTaskRunnerHandle::Get(),
                          base::Bind(&DrmDisplayHostManager::OnAddGraphicsDevice,
                                     weak_ptr_factory_.GetWeakPtr())));
           task_pending_ = true;
         }
         break;
       case DeviceEvent::CHANGE:
         task_pending_ = base::ThreadTaskRunnerHandle::Get()->PostTask(
             FROM_HERE,
@@ skipping 201 matching lines @@
 
   callback.Run(snapshots);
 }
 
 void DrmDisplayHostManager::NotifyDisplayDelegate() const {
   if (delegate_)
     delegate_->OnConfigurationChanged();
 }
 
 }  // namespace ui