Use constexpr TaskTraits constructor in chrome.

chrome/browser/mac/keystone_glue.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/mac/keystone_glue.h"
 
 #include <sys/mount.h>
 #include <sys/param.h>
 #include <sys/stat.h>
 
@@ skipping 53 matching lines @@
 class PerformBridge : public base::RefCountedThreadSafe<PerformBridge> {
  public:
 
   // Call |sel| on |target| with |arg| in a WorkerPool thread.
   // |target| and |arg| are retained, |arg| may be |nil|.
   static void PostPerform(id target, SEL sel, id arg) {
     DCHECK(target);
     DCHECK(sel);
 
     scoped_refptr<PerformBridge> op = new PerformBridge(target, sel, arg);
-    base::PostTaskWithTraits(
-        FROM_HERE, base::TaskTraits()
-                       .MayBlock()
-                       .WithPriority(base::TaskPriority::BACKGROUND)
-                       .WithShutdownBehavior(
-                           base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN),
-        base::Bind(&PerformBridge::Run, op.get()));
+    base::PostTaskWithTraits(FROM_HERE,
+                             {base::MayBlock(), base::TaskPriority::BACKGROUND,
+                              base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN},
+                             base::Bind(&PerformBridge::Run, op.get()));
   }
 
   // Convenience for the no-argument case.
   static void PostPerform(id target, SEL sel) {
     PostPerform(target, sel, nil);
   }
 
  private:
   // Allow RefCountedThreadSafe<> to delete.
   friend class base::RefCountedThreadSafe<PerformBridge>;
@@ skipping 1108 matching lines @@
   return [KeystoneGlue defaultKeystoneGlue] != nil;
 }
 
 base::string16 CurrentlyInstalledVersion() {
   KeystoneGlue* keystoneGlue = [KeystoneGlue defaultKeystoneGlue];
   NSString* version = [keystoneGlue currentlyInstalledVersion];
   return base::SysNSStringToUTF16(version);
 }
 
 }  // namespace keystone_glue