Use constexpr TaskTraits constructor in chrome.

chrome/browser/chromeos/extensions/file_manager/private_api_mount.cc

 // Copyright 2013 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/extensions/file_manager/private_api_mount.h"
 
 #include <string>
 
 #include "base/files/file_util.h"
 #include "base/format_macros.h"
@@ skipping 83 matching lines @@
           volume->mount_path().IsParent(path)) {
         is_under_downloads = true;
         break;
       }
     }
 
     if (is_under_downloads) {
       // For files under downloads, change the file permission and make it
       // readable from avfs/fuse if needed.
       base::PostTaskWithTraits(
-          FROM_HERE, base::TaskTraits().MayBlock().WithPriority(
-                         base::TaskPriority::USER_BLOCKING),
+          FROM_HERE, {base::MayBlock(), base::TaskPriority::USER_BLOCKING},
           base::Bind(&EnsureReadableFilePermissionAsync, path,
                      google_apis::CreateRelayCallback(
                          base::Bind(&FileManagerPrivateAddMountFunction::
                                         RunAfterMarkCacheFileAsMounted,
                                     this, path.BaseName()))));
     } else {
       RunAfterMarkCacheFileAsMounted(
           path.BaseName(), drive::FILE_ERROR_OK, path);
     }
   }
@@ skipping 130 matching lines @@
                 name(), request_id(), log_string.c_str(), result.size());
   }
 
   results_ =
       file_manager_private::GetVolumeMetadataList::Results::Create(result);
   SendResponse(true);
   return true;
 }
 
 }  // namespace extensions