Use constexpr TaskTraits constructor in base.

base/test/scoped_task_scheduler.h

Index: base/test/scoped_task_scheduler.h
diff --git a/base/test/scoped_task_scheduler.h b/base/test/scoped_task_scheduler.h
index 785443954b56e34097c3b0ec94f37dffaabdee1b..010b39e2af40fb8a28b0a22053471a7d20b88c10 100644
--- a/base/test/scoped_task_scheduler.h
+++ b/base/test/scoped_task_scheduler.h
@@ -41,8 +41,7 @@ namespace test {
 // base::PostTask(FROM_HERE, base::Bind(&RunLoop::Quit, &run_loop));
 // base::PostTask(FROM_HERE, base::Bind(&C));
 // base::PostTaskWithTraits(
-//     base::TaskTraits().WithShutdownBehavior(
-//         base::TaskShutdownBehavior::BLOCK_SHUTDOWN),
+//     {base::TaskShutdownBehavior::BLOCK_SHUTDOWN},
 //     base::Bind(&D));
 // run_loop.Run();  // Returns after running B and RunLoop::Quit.
 //