Use constexpr TaskTraits constructor in chrome.

chrome/browser/chromeos/login/login_utils_browsertest.cc

Index: chrome/browser/chromeos/login/login_utils_browsertest.cc
diff --git a/chrome/browser/chromeos/login/login_utils_browsertest.cc b/chrome/browser/chromeos/login/login_utils_browsertest.cc
index 9c6d463506abf6d3c5e820502929d9700a528743..a2d0e3f508e6d89dcae3ed7080a8006f981544d7 100644
--- a/chrome/browser/chromeos/login/login_utils_browsertest.cc
+++ b/chrome/browser/chromeos/login/login_utils_browsertest.cc
@@ -110,8 +110,7 @@ IN_PROC_BROWSER_TEST_F(LoginUtilsTest, RlzInitialized) {
     base::RunLoop loop;
     base::string16 rlz_string;
     base::PostTaskWithTraitsAndReply(
-        FROM_HERE, base::TaskTraits().MayBlock().WithPriority(
-                       base::TaskPriority::BACKGROUND),
+        FROM_HERE, {base::MayBlock(), base::TaskPriority::BACKGROUND},
         base::Bind(&GetAccessPointRlzInBackgroundThread,
                    rlz::RLZTracker::ChromeHomePage(), &rlz_string),
         loop.QuitClosure());