Fix virtual/override/final usage in Source/core/{animation,css,style}/.

Source/core/animation/animatable/AnimatableNeutral.h

Index: Source/core/animation/animatable/AnimatableNeutral.h
diff --git a/Source/core/animation/animatable/AnimatableNeutral.h b/Source/core/animation/animatable/AnimatableNeutral.h
index 76bb9b8b10904ec98094cf59edfd46be24f3dd1d..cca9f77bac2c53587d7e8abf24e570b301705f80 100644
--- a/Source/core/animation/animatable/AnimatableNeutral.h
+++ b/Source/core/animation/animatable/AnimatableNeutral.h
@@ -37,13 +37,13 @@ namespace blink {
 
 class AnimatableNeutral final : public AnimatableValue {
 public:
-    virtual ~AnimatableNeutral() { }
+    ~AnimatableNeutral() override { }
 
     DEFINE_INLINE_VIRTUAL_TRACE() { AnimatableValue::trace(visitor); }
 
 protected:
     static PassRefPtrWillBeRawPtr<AnimatableNeutral> create() { return adoptRefWillBeNoop(new AnimatableNeutral()); }
-    virtual PassRefPtrWillBeRawPtr<AnimatableValue> interpolateTo(const AnimatableValue* value, double fraction) const override
+    PassRefPtrWillBeRawPtr<AnimatableValue> interpolateTo(const AnimatableValue* value, double fraction) const override
     {
         ASSERT_NOT_REACHED();
         return nullptr;
@@ -51,8 +51,8 @@ protected:
 
 private:
     friend class AnimatableValue;
-    virtual AnimatableType type() const override { return TypeNeutral; }
-    virtual bool equalTo(const AnimatableValue* value) const override
+    AnimatableType type() const override { return TypeNeutral; }
+    bool equalTo(const AnimatableValue* value) const override
     {
         ASSERT_NOT_REACHED();
         return true;