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

Source/bindings/templates/interface.cpp

 {% extends 'interface_base.cpp' %}
 
 
 {##############################################################################}
 {% block indexed_property_getter %}
 {% if indexed_property_getter and not indexed_property_getter.is_custom %}
 {% set getter = indexed_property_getter %}
 static void indexedPropertyGetter(uint32_t index, const v8::PropertyCallbackInfo<v8::Value>& info)
 {
     {{cpp_class}}* impl = {{v8_class}}::toImpl(info.Holder());
@@ skipping 493 matching lines @@
     static int domTemplateKey; // This address is used for a key to look up the dom template.
     V8PerIsolateData* data = V8PerIsolateData::from(isolate);
     v8::Local<v8::FunctionTemplate> result = data->existingDOMTemplate(&domTemplateKey);
     if (!result.IsEmpty())
         return result;
 
     TRACE_EVENT_SCOPED_SAMPLING_STATE("blink", "BuildDOMTemplate");
     result = v8::FunctionTemplate::New(isolate, {{v8_class}}ConstructorCallback);
     v8::Local<v8::ObjectTemplate> instanceTemplate = result->InstanceTemplate();
     instanceTemplate->SetInternalFieldCount({{v8_class}}::internalFieldCount);
-    result->SetClassName(v8AtomicString(isolate, "{{cpp_class}}"));
+    instanceTemplate->Set(v8::Symbol::GetToStringTag(isolate), v8AtomicString(isolate, "{{cpp_class}}"));
     result->Inherit({{v8_class}}::domTemplate(isolate));
     data->setDOMTemplate(&domTemplateKey, result);
     return result;
 }
 
 {% endif %}
 {% endblock %}
 
 {##############################################################################}
 {% block overloaded_constructor %}
@@ skipping 505 matching lines @@
 }
 
 {% for method in methods if method.overloads and method.overloads.has_partial_overloads %}
 void {{v8_class}}::register{{method.name | blink_capitalize}}MethodForPartialInterface(void (*method)(const v8::FunctionCallbackInfo<v8::Value>&))
 {
     {{cpp_class}}V8Internal::{{method.name}}MethodForPartialInterface = method;
 }
 {% endfor %}
 {% endif %}
 {% endblock %}