replace OVERRIDE and FINAL with override and final in ash/

ash/system/chromeos/tray_tracing.cc

Index: ash/system/chromeos/tray_tracing.cc
diff --git a/ash/system/chromeos/tray_tracing.cc b/ash/system/chromeos/tray_tracing.cc
index c885e079ec8ee5ab89ff82d8ea82fd66edca955e..279bea9f8637eb78e2253c806a2bd705bea7b172 100644
--- a/ash/system/chromeos/tray_tracing.cc
+++ b/ash/system/chromeos/tray_tracing.cc
@@ -47,7 +47,7 @@ class DefaultTracingView : public ActionableView {
 
  private:
   // Overridden from ActionableView.
-  virtual bool PerformAction(const ui::Event& event) OVERRIDE {
+  virtual bool PerformAction(const ui::Event& event) override {
     Shell::GetInstance()->system_tray_delegate()->ShowChromeSlow();
     return true;
   }