Use constexpr TaskTraits constructor in chrome.

chrome/browser/ui/webui/about_ui.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/ui/webui/about_ui.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 302 matching lines @@
     DCHECK_CURRENTLY_ON(BrowserThread::UI);
     if (path_ == kKeyboardUtilsPath) {
       contents_ = ResourceBundle::GetSharedInstance()
                       .GetRawDataResource(IDR_KEYBOARD_UTILS_JS)
                       .as_string();
       ResponseOnUIThread();
       return;
     }
     // Load local Chrome OS credits from the disk.
     base::PostTaskWithTraitsAndReply(
-        FROM_HERE, base::TaskTraits().MayBlock().WithPriority(
-                       base::TaskPriority::BACKGROUND),
+        FROM_HERE, {base::MayBlock(), base::TaskPriority::BACKGROUND},
         base::Bind(&ChromeOSCreditsHandler::LoadCreditsFileAsync, this),
         base::Bind(&ChromeOSCreditsHandler::ResponseOnUIThread, this));
   }
 
   void LoadCreditsFileAsync() {
     base::FilePath credits_file_path(chrome::kChromeOSCreditsPath);
     if (!base::ReadFileToString(credits_file_path, &contents_)) {
       // File with credits not found, ResponseOnUIThread will load credits
       // from resources if contents_ is empty.
       contents_.clear();
@@ skipping 454 matching lines @@
   Profile* profile = Profile::FromWebUI(web_ui);
 
 #if !defined(OS_ANDROID)
   // Set up the chrome://theme/ source.
   ThemeSource* theme = new ThemeSource(profile);
   content::URLDataSource::Add(profile, theme);
 #endif
 
   content::URLDataSource::Add(profile, new AboutUIHTMLSource(name, profile));
 }