Use constexpr TaskTraits constructor in chrome.

chrome/browser/ui/webui/print_preview/extension_printer_handler.cc

 // Copyright 2015 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/print_preview/extension_printer_handler.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 62 matching lines @@
     std::unique_ptr<extensions::PrinterProviderPrintJob> job,
     const ExtensionPrinterHandler::PrintJobCallback& callback,
     bool success,
     const base::FilePath& pwg_file_path) {
   if (!success) {
     callback.Run(std::move(job));
     return;
   }
 
   base::PostTaskWithTraitsAndReplyWithResult(
-      FROM_HERE, base::TaskTraits()
-                     .WithShutdownBehavior(
-                         base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN)
-                     .MayBlock(),
+      FROM_HERE,
+      {base::MayBlock(), base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN},
       base::Bind(&UpdateJobFileInfoOnWorkerThread, pwg_file_path,
                  base::Passed(&job)),
       callback);
 }
 
 bool HasUsbPrinterProviderPermissions(const Extension* extension) {
   return extension->permissions_data() &&
         extension->permissions_data()->HasAPIPermission(
             extensions::APIPermission::kPrinterProvider) &&
         extension->permissions_data()->HasAPIPermission(
@@ skipping 266 matching lines @@
                 .Set("provisional", true)
                 .Build());
       }
     }
   }
 
   DCHECK_GT(pending_enumeration_count_, 0);
   pending_enumeration_count_--;
   callback.Run(*printer_list.Build().get(), pending_enumeration_count_ == 0);
 }