Use constexpr TaskTraits constructor in ui.

ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.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/events/ozone/layout/xkb/xkb_keyboard_layout_engine.h"
 
 #include <stddef.h>
 #include <xkbcommon/xkbcommon-names.h>
 
 #include <algorithm>
@@ skipping 668 matching lines @@
   current_layout_name_ = layout_name;
   for (const auto& entry : xkb_keymaps_) {
     if (entry.layout_name == layout_name) {
       SetKeymap(entry.keymap);
       return true;
     }
   }
   LoadKeymapCallback reply_callback = base::Bind(
       &XkbKeyboardLayoutEngine::OnKeymapLoaded, weak_ptr_factory_.GetWeakPtr());
   base::PostTaskWithTraits(
-      FROM_HERE, base::TaskTraits()
-                     .WithShutdownBehavior(
-                         base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN)
-                     .MayBlock(),
+      FROM_HERE,
+      {base::MayBlock(), base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN},
       base::Bind(&LoadKeymap, layout_name, base::ThreadTaskRunnerHandle::Get(),
                  reply_callback));
 #else
   NOTIMPLEMENTED();
 #endif  // defined(OS_CHROMEOS)
   return true;
 }
 
 void XkbKeyboardLayoutEngine::OnKeymapLoaded(
     const std::string& layout_name,
@@ skipping 266 matching lines @@
       close_index = layout_name.size();
     *layout_variant = layout_name.substr(parentheses_index + 1,
                                          close_index - parentheses_index - 1);
   } else if (dash_index != std::string::npos) {
     *layout_id = layout_name.substr(0, dash_index);
     *layout_variant = layout_name.substr(dash_index + 1);
   }
 }
 
 }  // namespace ui