Use constexpr TaskTraits constructor in chrome.

chrome/browser/ui/webui/chromeos/image_source.cc

Index: chrome/browser/ui/webui/chromeos/image_source.cc
diff --git a/chrome/browser/ui/webui/chromeos/image_source.cc b/chrome/browser/ui/webui/chromeos/image_source.cc
index d24f282a6fd537138e7c9d24d234a13db775a6bf..743d22e8c678efde77fada21efb24e69c388ec5d 100644
--- a/chrome/browser/ui/webui/chromeos/image_source.cc
+++ b/chrome/browser/ui/webui/chromeos/image_source.cc
@@ -74,9 +74,7 @@ void ImageSource::StartDataRequest(
   const base::FilePath asset_dir(FILE_PATH_LITERAL(chrome::kChromeOSAssetPath));
   const base::FilePath image_path = asset_dir.AppendASCII(path);
   base::PostTaskWithTraitsAndReplyWithResult(
-      FROM_HERE,
-      base::TaskTraits().MayBlock().WithPriority(
-          base::TaskPriority::USER_VISIBLE),
+      FROM_HERE, {base::MayBlock(), base::TaskPriority::USER_VISIBLE},
       base::Bind(&base::PathExists, image_path),
       base::Bind(&ImageSource::StartDataRequestAfterPathExists,
                  weak_factory_.GetWeakPtr(), image_path, got_data_callback));