Standardize usage of virtual/override/final in ui/

ui/gfx/animation/slide_animation.h

Index: ui/gfx/animation/slide_animation.h
diff --git a/ui/gfx/animation/slide_animation.h b/ui/gfx/animation/slide_animation.h
index 3795e368141191dddcd21b2caea4f328794acc10..58effac3f1d02eb8b84894887b297619d9ca9f14 100644
--- a/ui/gfx/animation/slide_animation.h
+++ b/ui/gfx/animation/slide_animation.h
@@ -47,7 +47,7 @@ namespace gfx {
 class GFX_EXPORT SlideAnimation : public LinearAnimation {
  public:
   explicit SlideAnimation(AnimationDelegate* target);
-  virtual ~SlideAnimation();
+  ~SlideAnimation() override;
 
   // Set the animation back to the 0 state.
   virtual void Reset();
@@ -66,7 +66,7 @@ class GFX_EXPORT SlideAnimation : public LinearAnimation {
   int GetSlideDuration() const { return slide_duration_; }
   void SetTweenType(Tween::Type tween_type) { tween_type_ = tween_type; }
 
-  virtual double GetCurrentValue() const override;
+  double GetCurrentValue() const override;
   bool IsShowing() const { return showing_; }
   bool IsClosing() const { return !showing_ && value_end_ < value_current_; }
 
@@ -74,7 +74,7 @@ class GFX_EXPORT SlideAnimation : public LinearAnimation {
 
  private:
   // Overridden from Animation.
-  virtual void AnimateToState(double state) override;
+  void AnimateToState(double state) override;
 
   AnimationDelegate* target_;