Use constexpr TaskTraits constructor in chrome.

chrome/browser/ui/views/chrome_views_delegate_win.cc

 // Copyright 2017 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/views/chrome_views_delegate.h"
 
 #include <dwmapi.h>
 #include <shellapi.h>
 
 #include "base/profiler/scoped_tracker.h"
@@ skipping 149 matching lines @@
   if (!appbar_autohide_edge_map_.count(monitor))
     appbar_autohide_edge_map_[monitor] = EDGE_BOTTOM;
 
   // We use the SHAppBarMessage API to get the taskbar autohide state. This API
   // spins a modal loop which could cause callers to be reentered. To avoid
   // that we retrieve the taskbar state in a worker thread.
   if (monitor && !in_autohide_edges_callback_) {
     // TODO(robliao): Annotate this task with .WithCOM() once supported.
     // https://crbug.com/662122
     base::PostTaskWithTraitsAndReplyWithResult(
-        FROM_HERE,
-        base::TaskTraits().MayBlock().WithPriority(
-            base::TaskPriority::USER_BLOCKING),
+        FROM_HERE, {base::MayBlock(), base::TaskPriority::USER_BLOCKING},
         base::Bind(&GetAppbarAutohideEdgesOnWorkerThread, monitor),
         base::Bind(&ChromeViewsDelegate::OnGotAppbarAutohideEdges,
                    weak_factory_.GetWeakPtr(), callback, monitor,
                    appbar_autohide_edge_map_[monitor]));
   }
   return appbar_autohide_edge_map_[monitor];
 }
 
 void ChromeViewsDelegate::OnGotAppbarAutohideEdges(
     const base::Closure& callback,
     HMONITOR monitor,
     int returned_edges,
     int edges) {
   appbar_autohide_edge_map_[monitor] = edges;
   if (returned_edges == edges)
     return;
 
   base::AutoReset<bool> in_callback_setter(&in_autohide_edges_callback_, true);
   callback.Run();
 }