Use constexpr TaskTraits constructor in chrome.

chrome/browser/extensions/api/messaging/native_process_launcher.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/extensions/api/messaging/native_process_launcher.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 90 matching lines @@
 void NativeProcessLauncherImpl::Core::Detach() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
   detached_ = true;
 }
 
 void NativeProcessLauncherImpl::Core::Launch(
     const GURL& origin,
     const std::string& native_host_name,
     const LaunchedCallback& callback) {
   base::PostTaskWithTraits(FROM_HERE,
-                           base::TaskTraits().MayBlock().WithPriority(
-                               base::TaskPriority::USER_VISIBLE),
+                           {base::MayBlock(), base::TaskPriority::USER_VISIBLE},
                            base::BindOnce(&Core::DoLaunchOnThreadPool, this,
                                           origin, native_host_name, callback));
 }
 
 void NativeProcessLauncherImpl::Core::DoLaunchOnThreadPool(
     const GURL& origin,
     const std::string& native_host_name,
     const LaunchedCallback& callback) {
   if (!NativeMessagingHostManifest::IsValidName(native_host_name)) {
     PostErrorResult(callback, RESULT_INVALID_NAME);
@@ skipping 146 matching lines @@
   intptr_t window_handle = 0;
 #if defined(OS_WIN)
   window_handle = reinterpret_cast<intptr_t>(
       views::HWNDForNativeView(native_view));
 #endif
   return std::unique_ptr<NativeProcessLauncher>(
       new NativeProcessLauncherImpl(allow_user_level_hosts, window_handle));
 }
 
 }  // namespace extensions