Use constexpr TaskTraits constructor in chrome.

chrome/browser/chromeos/login/users/wallpaper/wallpaper_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 "chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.h"
 
 #include <utility>
 
 #include "ash/ash_constants.h"
 #include "ash/public/interfaces/constants.mojom.h"
@@ skipping 943 matching lines @@
           ? user_manager::UserManager::Get()->GetActiveUser()->GetAccountId()
           : user_manager::SignInAccountId());
 }
 
 void WallpaperManager::OnDeviceWallpaperExists(const AccountId& account_id,
                                                const std::string& url,
                                                const std::string& hash,
                                                bool exist) {
   if (exist) {
     base::PostTaskWithTraitsAndReplyWithResult(
-        FROM_HERE, base::TaskTraits().MayBlock(),
+        FROM_HERE, {base::MayBlock()},
         base::Bind(&CheckDeviceWallpaperMatchHash, GetDeviceWallpaperFilePath(),
                    hash),
         base::Bind(&WallpaperManager::OnCheckDeviceWallpaperMatchHash,
                    weak_factory_.GetWeakPtr(), account_id, url, hash));
   } else {
     GURL device_wallpaper_url(url);
     device_wallpaper_downloader_.reset(new CustomizationWallpaperDownloader(
         g_browser_process->system_request_context(), device_wallpaper_url,
         GetDeviceWallpaperDir(), GetDeviceWallpaperFilePath(),
         base::Bind(&WallpaperManager::OnDeviceWallpaperDownloaded,
                    weak_factory_.GetWeakPtr(), account_id, hash)));
     device_wallpaper_downloader_->Start();
   }
 }
 
 void WallpaperManager::OnDeviceWallpaperDownloaded(const AccountId& account_id,
                                                    const std::string& hash,
                                                    bool success,
                                                    const GURL& url) {
   if (!success) {
     LOG(ERROR) << "Failed to download the device wallpaper. Fallback to "
                   "default wallpaper.";
     SetDefaultWallpaperDelayed(account_id);
     return;
   }
 
   base::PostTaskWithTraitsAndReplyWithResult(
-      FROM_HERE, base::TaskTraits().MayBlock(),
+      FROM_HERE, {base::MayBlock()},
       base::Bind(&CheckDeviceWallpaperMatchHash, GetDeviceWallpaperFilePath(),
                  hash),
       base::Bind(&WallpaperManager::OnCheckDeviceWallpaperMatchHash,
                  weak_factory_.GetWeakPtr(), account_id, url.spec(), hash));
 }
 
 void WallpaperManager::OnCheckDeviceWallpaperMatchHash(
     const AccountId& account_id,
     const std::string& url,
     const std::string& hash,
@@ skipping 275 matching lines @@
 }
 
 bool WallpaperManager::SetDeviceWallpaperIfApplicable(
     const AccountId& account_id) {
   std::string url;
   std::string hash;
   if (ShouldSetDeviceWallpaper(account_id, &url, &hash)) {
     // Check if the device wallpaper exists and matches the hash. If so, use it
     // directly. Otherwise download it first.
     base::PostTaskWithTraitsAndReplyWithResult(
-        FROM_HERE, base::TaskTraits().MayBlock(),
+        FROM_HERE, {base::MayBlock()},
         base::Bind(&base::PathExists, GetDeviceWallpaperFilePath()),
         base::Bind(&WallpaperManager::OnDeviceWallpaperExists,
                    weak_factory_.GetWeakPtr(), account_id, url, hash));
     return true;
   }
   return false;
 }
 
 void WallpaperManager::UserChangedChildStatus(user_manager::User* user) {
   SetUserWallpaperNow(user->GetAccountId());
@@ skipping 87 matching lines @@
 
   UMA_HISTOGRAM_ENUMERATION(
       "Ash.Wallpaper.Apps",
       wallpaper_manager_util::ShouldUseAndroidWallpapersApp(profile)
           ? WALLPAPERS_APP_ANDROID
           : WALLPAPERS_PICKER_APP_CHROMEOS,
       WALLPAPERS_APPS_NUM);
 }
 
 }  // namespace chromeos