Use constexpr TaskTraits constructor in chrome.

chrome/browser/chrome_browser_main_linux.cc

Index: chrome/browser/chrome_browser_main_linux.cc
diff --git a/chrome/browser/chrome_browser_main_linux.cc b/chrome/browser/chrome_browser_main_linux.cc
index fadd55cc0398d07c5d2c41d7b2fd73e780dc603c..d3f5b5d636f8213a9aa0cc1b73ee8df03346732a 100644
--- a/chrome/browser/chrome_browser_main_linux.cc
+++ b/chrome/browser/chrome_browser_main_linux.cc
@@ -50,9 +50,7 @@ void ChromeBrowserMainPartsLinux::PreProfileInit() {
   // g_browser_process.  This happens in PreCreateThreads.
   // base::GetLinuxDistro() will initialize its value if needed.
   base::PostTaskWithTraits(
-      FROM_HERE,
-      base::TaskTraits().MayBlock().WithPriority(
-          base::TaskPriority::BACKGROUND),
+      FROM_HERE, {base::MayBlock(), base::TaskPriority::BACKGROUND},
       base::BindOnce(base::IgnoreResult(&base::GetLinuxDistro)));
 #endif