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

Source/bindings/tests/results/core/V8TestInterfaceWillBeGarbageCollected.cpp

Index: Source/bindings/tests/results/core/V8TestInterfaceWillBeGarbageCollected.cpp
diff --git a/Source/bindings/tests/results/core/V8TestInterfaceWillBeGarbageCollected.cpp b/Source/bindings/tests/results/core/V8TestInterfaceWillBeGarbageCollected.cpp
index e47a6d0a7ba2ea6760d86f278d3d8707a28fe461..fc4977ac41de8b91eef9b9677fb1718d71925cbd 100644
--- a/Source/bindings/tests/results/core/V8TestInterfaceWillBeGarbageCollected.cpp
+++ b/Source/bindings/tests/results/core/V8TestInterfaceWillBeGarbageCollected.cpp
@@ -147,7 +147,7 @@ v8::Local<v8::FunctionTemplate> V8TestInterfaceWillBeGarbageCollectedConstructor
     result = v8::FunctionTemplate::New(isolate, V8TestInterfaceWillBeGarbageCollectedConstructorCallback);
     v8::Local<v8::ObjectTemplate> instanceTemplate = result->InstanceTemplate();
     instanceTemplate->SetInternalFieldCount(V8TestInterfaceWillBeGarbageCollected::internalFieldCount);
-    result->SetClassName(v8AtomicString(isolate, "TestInterfaceWillBeGarbageCollected"));
+    instanceTemplate->Set(v8::Symbol::GetToStringTag(isolate), v8AtomicString(isolate, "TestInterfaceWillBeGarbageCollected"));
     result->Inherit(V8TestInterfaceWillBeGarbageCollected::domTemplate(isolate));
     data->setDOMTemplate(&domTemplateKey, result);
     return result;
@@ -189,6 +189,10 @@ static void installV8TestInterfaceWillBeGarbageCollectedTemplate(v8::Local<v8::F
     };
     V8DOMConfiguration::installMethod(isolate, instanceTemplate, defaultSignature, static_cast<v8::PropertyAttribute>(v8::DontDelete | v8::ReadOnly), funcMethodConfiguration);
 
+    instanceTemplate->Set(v8::Symbol::GetToStringTag(isolate), v8AtomicString(isolate, "TestInterfaceWillBeGarbageCollected"));
+
+    prototypeTemplate->Set(v8::Symbol::GetToStringTag(isolate), v8AtomicString(isolate, "TestInterfaceWillBeGarbageCollectedPrototype"));
+
     // Custom toString template
     functionTemplate->Set(v8AtomicString(isolate, "toString"), V8PerIsolateData::from(isolate)->toStringTemplate());
 }