[DO NOT LAND] Set @@toStringTag for DOM object prototypes

Source/bindings/tests/results/core/V8SVGTestInterface.cpp

Index: Source/bindings/tests/results/core/V8SVGTestInterface.cpp
diff --git a/Source/bindings/tests/results/core/V8SVGTestInterface.cpp b/Source/bindings/tests/results/core/V8SVGTestInterface.cpp
index f547dbe95ae831fd2951e481a3c68c6b927e4d5a..d77c97b046c6d67fb3e7af92646de2aa608d45fb 100644
--- a/Source/bindings/tests/results/core/V8SVGTestInterface.cpp
+++ b/Source/bindings/tests/results/core/V8SVGTestInterface.cpp
@@ -85,6 +85,10 @@ static void installV8SVGTestInterfaceTemplate(v8::Local<v8::FunctionTemplate> fu
     v8::Local<v8::ObjectTemplate> prototypeTemplate = functionTemplate->PrototypeTemplate();
     ALLOW_UNUSED_LOCAL(prototypeTemplate);
 
+    instanceTemplate->Set(v8::Symbol::GetToStringTag(isolate), v8AtomicString(isolate, "SVGTestInterface"));
+
+    prototypeTemplate->Set(v8::Symbol::GetToStringTag(isolate), v8AtomicString(isolate, "SVGTestInterfacePrototype"));
+
     // Custom toString template
     functionTemplate->Set(v8AtomicString(isolate, "toString"), V8PerIsolateData::from(isolate)->toStringTemplate());
 }