Introduce DEFINE_ANIMATABLE_VALUE_TYPE_CASTS to replace manual toFoo() for animatable value

Source/core/animation/AnimatableVisibility.h

Index: Source/core/animation/AnimatableVisibility.h
diff --git a/Source/core/animation/AnimatableVisibility.h b/Source/core/animation/AnimatableVisibility.h
index c057b5a95e7f5ae7bef1a78937a80e4785dee18f..bbd377105d0984e159876200673d1df0dc342fbe 100644
--- a/Source/core/animation/AnimatableVisibility.h
+++ b/Source/core/animation/AnimatableVisibility.h
@@ -59,11 +59,7 @@ private:
     const EVisibility m_visibility;
 };
 
-inline const AnimatableVisibility* toAnimatableVisibility(const AnimatableValue* value)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(value && value->isVisibility());
-    return static_cast<const AnimatableVisibility*>(value);
-}
+DEFINE_ANIMATABLE_VALUE_TYPE_CASTS(AnimatableVisibility, isVisibility());
 
 } // namespace WebCore