Use constexpr TaskTraits constructor in chrome.

chrome/browser/chromeos/platform_keys/platform_keys.cc

Index: chrome/browser/chromeos/platform_keys/platform_keys.cc
diff --git a/chrome/browser/chromeos/platform_keys/platform_keys.cc b/chrome/browser/chromeos/platform_keys/platform_keys.cc
index cc3ca6f56f2201530aa3d3bec269a9ed5c86c473..0b2f0a60207773796b68b10057b442a51f13155b 100644
--- a/chrome/browser/chromeos/platform_keys/platform_keys.cc
+++ b/chrome/browser/chromeos/platform_keys/platform_keys.cc
@@ -71,10 +71,9 @@ void IntersectCertificates(
   // chrome.platformKeys.selectClientCertificates extensions API. Completion
   // does not affect browser responsiveness, hence the BACKGROUND priority.
   base::PostTaskWithTraitsAndReply(
-      FROM_HERE, base::TaskTraits()
-                     .WithPriority(base::TaskPriority::BACKGROUND)
-                     .WithShutdownBehavior(
-                         base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN),
+      FROM_HERE,
+      {base::TaskPriority::BACKGROUND,
+       base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN},
       base::Bind(&IntersectOnWorkerThread, certs1, certs2, intersection_ptr),
       base::Bind(callback, base::Passed(&intersection)));
 }