replace OVERRIDE and FINAL with override and final in ash/

ash/system/tray/default_system_tray_delegate.cc

Index: ash/system/tray/default_system_tray_delegate.cc
diff --git a/ash/system/tray/default_system_tray_delegate.cc b/ash/system/tray/default_system_tray_delegate.cc
index fda48075ec2a16db115abc50ec9a13f781bd3346..1d99fb92eca45a9baf4922d9c48490c7116a4577 100644
--- a/ash/system/tray/default_system_tray_delegate.cc
+++ b/ash/system/tray/default_system_tray_delegate.cc
@@ -21,13 +21,13 @@ class DefaultVolumnControlDelegate : public VolumeControlDelegate {
   DefaultVolumnControlDelegate() {}
   virtual ~DefaultVolumnControlDelegate() {}
 
-  virtual bool HandleVolumeMute(const ui::Accelerator& accelerator) OVERRIDE {
+  virtual bool HandleVolumeMute(const ui::Accelerator& accelerator) override {
     return true;
   }
-  virtual bool HandleVolumeDown(const ui::Accelerator& accelerator) OVERRIDE {
+  virtual bool HandleVolumeDown(const ui::Accelerator& accelerator) override {
     return true;
   }
-  virtual bool HandleVolumeUp(const ui::Accelerator& accelerator) OVERRIDE {
+  virtual bool HandleVolumeUp(const ui::Accelerator& accelerator) override {
     return true;
   }