Introduce DEFINE_RENDER_OBJECT_TYPE_CASTS to replace manual toRenderFoo, and use it

Source/core/rendering/RenderMenuList.h

Index: Source/core/rendering/RenderMenuList.h
diff --git a/Source/core/rendering/RenderMenuList.h b/Source/core/rendering/RenderMenuList.h
index 530f7a950720fb70491229a6552e6b9afc34fa77..29551c52aad286b0d02c082fb12366d476ac1352 100644
--- a/Source/core/rendering/RenderMenuList.h
+++ b/Source/core/rendering/RenderMenuList.h
@@ -141,14 +141,7 @@ private:
     bool m_popupIsVisible;
 };
 
-inline RenderMenuList* toRenderMenuList(RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isMenuList());
-    return static_cast<RenderMenuList*>(object);
-}
-
-// This will catch anyone doing an unnecessary cast.
-void toRenderMenuList(const RenderMenuList*);
+DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderMenuList, isMenuList());
 
 }