Use constexpr TaskTraits constructor in base (part 2).

base/task_scheduler/scheduler_single_thread_task_runner_manager.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 "base/task_scheduler/scheduler_single_thread_task_runner_manager.h"
 
 #include <algorithm>
 #include <memory>
 #include <string>
 #include <utility>
@@ skipping 196 matching lines @@
     MSG msg;
     if (PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE) != FALSE) {
       auto pump_message_task =
           MakeUnique<Task>(FROM_HERE,
                            Bind(
                                [](MSG msg) {
                                  TranslateMessage(&msg);
                                  DispatchMessage(&msg);
                                },
                                std::move(msg)),
-                           TaskTraits().MayBlock(), TimeDelta());
+                           TaskTraits(MayBlock()), TimeDelta());
       if (task_tracker_->WillPostTask(pump_message_task.get())) {
         bool was_empty =
             message_pump_sequence_->PushTask(std::move(pump_message_task));
         DCHECK(was_empty) << "GetWorkFromWindowsMessageQueue() does not expect "
                              "queueing of pump tasks.";
         return message_pump_sequence_;
       }
     }
     return nullptr;
   }
@@ skipping 259 matching lines @@
                      });
     DCHECK(worker_iter != workers_.end());
     worker_to_destroy = std::move(*worker_iter);
     workers_.erase(worker_iter);
   }
   worker_to_destroy->Cleanup();
 }
 
 }  // namespace internal
 }  // namespace base