Use constexpr TaskTraits constructor in chrome.

chrome/browser/feature_engagement_tracker/feature_engagement_tracker_factory.cc

Index: chrome/browser/feature_engagement_tracker/feature_engagement_tracker_factory.cc
diff --git a/chrome/browser/feature_engagement_tracker/feature_engagement_tracker_factory.cc b/chrome/browser/feature_engagement_tracker/feature_engagement_tracker_factory.cc
index 71ea2406dd658f274cb08c8ad10f2793b023d6a1..66bb1629937c29139899b344e510fc40e4562a08 100644
--- a/chrome/browser/feature_engagement_tracker/feature_engagement_tracker_factory.cc
+++ b/chrome/browser/feature_engagement_tracker/feature_engagement_tracker_factory.cc
@@ -43,8 +43,7 @@ KeyedService* FeatureEngagementTrackerFactory::BuildServiceInstanceFor(
 
   scoped_refptr<base::SequencedTaskRunner> background_task_runner =
       base::CreateSequencedTaskRunnerWithTraits(
-          base::TaskTraits().MayBlock().WithPriority(
-              base::TaskPriority::BACKGROUND));
+          {base::MayBlock(), base::TaskPriority::BACKGROUND});
 
   base::FilePath storage_dir = profile->GetPath().Append(
       chrome::kFeatureEngagementTrackerStorageDirname);