C++11 override style change for athena

athena/screen_lock/chrome/chrome_screen_lock_manager.cc

Index: athena/screen_lock/chrome/chrome_screen_lock_manager.cc
diff --git a/athena/screen_lock/chrome/chrome_screen_lock_manager.cc b/athena/screen_lock/chrome/chrome_screen_lock_manager.cc
index 628b0d860c07be4b6e9b12972c638bfaa6ec5819..c22c85878a2ec3ecdc685ec8832e57745d62d303 100644
--- a/athena/screen_lock/chrome/chrome_screen_lock_manager.cc
+++ b/athena/screen_lock/chrome/chrome_screen_lock_manager.cc
@@ -28,19 +28,19 @@ class ChromeScreenLockManager : public ScreenLockManagerBase,
   void Init();
 
  protected:
-  virtual ~ChromeScreenLockManager();
+  ~ChromeScreenLockManager() override;
 
  private:
   // ScreenLockManager:
-  virtual void LockScreen() override;
+  void LockScreen() override;
 
   // AcceleratorHandler:
-  virtual bool IsCommandEnabled(int command_id) const override;
-  virtual bool OnAcceleratorFired(int command_id,
+  bool IsCommandEnabled(int command_id) const override;
+  bool OnAcceleratorFired(int command_id,
                                   const ui::Accelerator& accelerator) override;
 
   // PowerButtonObserver:
-  virtual void OnPowerButtonStateChanged(State state) override;
+  void OnPowerButtonStateChanged(State state) override;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeScreenLockManager);
 };