Standardize usage of virtual/override/final specifiers.

ash/wm/always_on_top_controller.h

Index: ash/wm/always_on_top_controller.h
diff --git a/ash/wm/always_on_top_controller.h b/ash/wm/always_on_top_controller.h
index c813ea2c4281c27a374d7b5642cacb600f0d3a63..eeb1339151ef783df5a8899b9aa4b520e57fad63 100644
--- a/ash/wm/always_on_top_controller.h
+++ b/ash/wm/always_on_top_controller.h
@@ -22,7 +22,7 @@ namespace ash {
 class AlwaysOnTopController : public aura::WindowObserver {
  public:
   AlwaysOnTopController();
-  virtual ~AlwaysOnTopController();
+  ~AlwaysOnTopController() override;
 
   // Sets the container for always on top windows.
   void SetAlwaysOnTopContainer(aura::Window* always_on_top_container);
@@ -32,12 +32,12 @@ class AlwaysOnTopController : public aura::WindowObserver {
 
  private:
   // Overridden from aura::WindowObserver:
-  virtual void OnWindowAdded(aura::Window* child) override;
-  virtual void OnWillRemoveWindow(aura::Window* child) override;
-  virtual void OnWindowPropertyChanged(aura::Window* window,
-                                       const void* key,
-                                       intptr_t old) override;
-  virtual void OnWindowDestroyed(aura::Window* window) override;
+  void OnWindowAdded(aura::Window* child) override;
+  void OnWillRemoveWindow(aura::Window* child) override;
+  void OnWindowPropertyChanged(aura::Window* window,
+                               const void* key,
+                               intptr_t old) override;
+  void OnWindowDestroyed(aura::Window* window) override;
 
   aura::Window* always_on_top_container_;