Introduce DEFINE_RENDER_OBJECT_TYPE_CASTS to replace manual toRenderFoo, and use it

Source/core/rendering/svg/RenderSVGTextPath.h

Index: Source/core/rendering/svg/RenderSVGTextPath.h
diff --git a/Source/core/rendering/svg/RenderSVGTextPath.h b/Source/core/rendering/svg/RenderSVGTextPath.h
index 690604c36c23d00ee45688302358624f7a97a940..ba9ad79ecb506369e73fc29d276677572ac806c3 100644
--- a/Source/core/rendering/svg/RenderSVGTextPath.h
+++ b/Source/core/rendering/svg/RenderSVGTextPath.h
@@ -42,14 +42,7 @@ private:
     Path m_layoutPath;
 };
 
-inline RenderSVGTextPath* toRenderSVGTextPath(RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isSVGTextPath());
-    return static_cast<RenderSVGTextPath*>(object);
-}
-
-// This will catch anyone doing an unnecessary cast.
-void toRenderSVGTextPath(const RenderSVGTextPath*);
+DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderSVGTextPath, isSVGTextPath());
 
 }