Introduce DEFINE_RENDER_OBJECT_TYPE_CASTS to replace manual toRenderFoo, and use it

Source/core/rendering/RenderLayerModelObject.h

Index: Source/core/rendering/RenderLayerModelObject.h
diff --git a/Source/core/rendering/RenderLayerModelObject.h b/Source/core/rendering/RenderLayerModelObject.h
index 64da75fc1e9dccff0743dac5cc20fb2efcfc985d..559c4ea8d0cf0dc164b50cebe6840eca7d5c6ea6 100644
--- a/Source/core/rendering/RenderLayerModelObject.h
+++ b/Source/core/rendering/RenderLayerModelObject.h
@@ -77,20 +77,7 @@ private:
     static bool s_layerWasSelfPainting;
 };
 
-inline RenderLayerModelObject* toRenderLayerModelObject(RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isLayerModelObject());
-    return static_cast<RenderLayerModelObject*>(object);
-}
-
-inline const RenderLayerModelObject* toRenderLayerModelObject(const RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isLayerModelObject());
-    return static_cast<const RenderLayerModelObject*>(object);
-}
-
-// This will catch anyone doing an unnecessary cast.
-void toRenderLayerModelObject(const RenderLayerModelObject*);
+DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderLayerModelObject, isLayerModelObject());
 
 } // namespace WebCore