replace OVERRIDE and FINAL with override and final in ash/

ash/system/chromeos/network/tray_vpn.cc

Index: ash/system/chromeos/network/tray_vpn.cc
diff --git a/ash/system/chromeos/network/tray_vpn.cc b/ash/system/chromeos/network/tray_vpn.cc
index 01547ae11a11c3f707f44f06930cb8a42b2aa467..545a5bae618db0e67d4be59fcff83b2a3a50b3de 100644
--- a/ash/system/chromeos/network/tray_vpn.cc
+++ b/ash/system/chromeos/network/tray_vpn.cc
@@ -67,7 +67,7 @@ class VpnDefaultView : public TrayItemMore,
   }
 
   // ui::network_icon::AnimationObserver
-  virtual void NetworkIconChanged() OVERRIDE {
+  virtual void NetworkIconChanged() override {
     Update();
   }