Use constexpr TaskTraits constructor in chrome.

chrome/browser/chromeos/platform_keys/platform_keys.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/platform_keys/platform_keys.h"
 
 #include <map>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 53 matching lines @@
     const net::CertificateList& certs2,
     const base::Callback<void(std::unique_ptr<net::CertificateList>)>&
         callback) {
   std::unique_ptr<net::CertificateList> intersection(new net::CertificateList);
   net::CertificateList* const intersection_ptr = intersection.get();
 
   // This is triggered by a call to the
   // chrome.platformKeys.selectClientCertificates extensions API. Completion
   // does not affect browser responsiveness, hence the BACKGROUND priority.
   base::PostTaskWithTraitsAndReply(
-      FROM_HERE, base::TaskTraits()
-                     .WithPriority(base::TaskPriority::BACKGROUND)
-                     .WithShutdownBehavior(
-                         base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN),
+      FROM_HERE,
+      {base::TaskPriority::BACKGROUND,
+       base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN},
       base::Bind(&IntersectOnWorkerThread, certs1, certs2, intersection_ptr),
       base::Bind(callback, base::Passed(&intersection)));
 }
 
 }  // namespace platform_keys
 
 }  // namespace chromeos