Standardize usage of virtual/override/final in cc/

cc/animation/scroll_offset_animation_curve.h

Index: cc/animation/scroll_offset_animation_curve.h
diff --git a/cc/animation/scroll_offset_animation_curve.h b/cc/animation/scroll_offset_animation_curve.h
index 197a431518c48db1c6c549cff47fe7c44fc98284..0c8692ad60b3fdda220770b9f5677e9ae1c347bd 100644
--- a/cc/animation/scroll_offset_animation_curve.h
+++ b/cc/animation/scroll_offset_animation_curve.h
@@ -21,7 +21,7 @@ class CC_EXPORT ScrollOffsetAnimationCurve : public AnimationCurve {
       const gfx::ScrollOffset& target_value,
       scoped_ptr<TimingFunction> timing_function);
 
-  virtual ~ScrollOffsetAnimationCurve();
+  ~ScrollOffsetAnimationCurve() override;
 
   void SetInitialValue(const gfx::ScrollOffset& initial_value);
   gfx::ScrollOffset GetValue(double t) const;
@@ -29,9 +29,9 @@ class CC_EXPORT ScrollOffsetAnimationCurve : public AnimationCurve {
   void UpdateTarget(double t, const gfx::ScrollOffset& new_target);
 
   // AnimationCurve implementation
-  virtual double Duration() const override;
-  virtual CurveType Type() const override;
-  virtual scoped_ptr<AnimationCurve> Clone() const override;
+  double Duration() const override;
+  CurveType Type() const override;
+  scoped_ptr<AnimationCurve> Clone() const override;
 
  private:
   ScrollOffsetAnimationCurve(const gfx::ScrollOffset& target_value,