Use constexpr TaskTraits constructor in components.

components/nacl/browser/nacl_file_host.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 "components/nacl/browser/nacl_file_host.h"
 
 #include <stddef.h>
 #include <stdint.h>
 #include <utility>
 
@@ skipping 161 matching lines @@
 }  // namespace
 
 namespace nacl_file_host {
 
 void GetReadonlyPnaclFd(
     scoped_refptr<nacl::NaClHostMessageFilter> nacl_host_message_filter,
     const std::string& filename,
     bool is_executable,
     IPC::Message* reply_msg) {
   base::PostTaskWithTraits(
-      FROM_HERE, base::TaskTraits().MayBlock(),
+      FROM_HERE, {base::MayBlock()},
       base::Bind(&DoOpenPnaclFile, nacl_host_message_filter, filename,
                  is_executable, reply_msg));
 }
 
 // This function is security sensitive.  Be sure to check with a security
 // person before you modify it.
 bool PnaclCanOpenFile(const std::string& filename,
                       base::FilePath* file_to_open) {
   if (filename.length() > kMaxFileLength)
     return false;
@@ skipping 60 matching lines @@
                                             site_instance->GetSiteURL(),
                                             file_url)) {
     NotifyRendererOfError(nacl_host_message_filter.get(), reply_msg);
     return;
   }
 
   // The URL is part of the current app. Now query the extension system for the
   // file path and convert that to a file descriptor. This should be done on a
   // blocking pool thread.
   base::PostTaskWithTraits(
-      FROM_HERE, base::TaskTraits().MayBlock(),
+      FROM_HERE, {base::MayBlock()},
       base::Bind(&DoOpenNaClExecutableOnThreadPool, nacl_host_message_filter,
                  file_url, enable_validation_caching, reply_msg));
 }
 
 }  // namespace nacl_file_host