Add constexpr TaskTraits constructor.

base/task_scheduler/task_traits.cc

 // Copyright 2016 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/task_traits.h"
 
 #include <stddef.h>
 
 #include <ostream>
 
 #include "base/logging.h"
 
 namespace base {
 
-// Do not rely on defaults hard-coded below beyond the guarantees described in
-// the header; anything else is subject to change. Tasks should explicitly
-// request defaults if the behavior is critical to the task.
-TaskTraits::TaskTraits()
-    : may_block_(false),
-      with_base_sync_primitives_(false),
-      priority_(TaskPriority::INHERITED),
-      shutdown_behavior_(TaskShutdownBehavior::SKIP_ON_SHUTDOWN) {}
-
-TaskTraits::~TaskTraits() = default;
-
 TaskTraits& TaskTraits::MayBlock() {
   may_block_ = true;
   return *this;
 }
 
 TaskTraits& TaskTraits::WithBaseSyncPrimitives() {
   with_base_sync_primitives_ = true;
   return *this;
 }
 
@@ skipping 42 matching lines @@
   return os;
 }
 
 std::ostream& operator<<(std::ostream& os,
                          const TaskShutdownBehavior& shutdown_behavior) {
   os << TaskShutdownBehaviorToString(shutdown_behavior);
   return os;
 }
 
 }  // namespace base