Fix V8 bindings for named constructors to set prototype object correctly

third_party/WebKit/Source/bindings/templates/interface.cpp.tmpl

Index: third_party/WebKit/Source/bindings/templates/interface.cpp.tmpl
diff --git a/third_party/WebKit/Source/bindings/templates/interface.cpp.tmpl b/third_party/WebKit/Source/bindings/templates/interface.cpp.tmpl
index 9e0e34b4c0b90182edec736c3baa2777d8d7907b..25a7a0411da11851aa28fffec8261c970344edbf 100644
--- a/third_party/WebKit/Source/bindings/templates/interface.cpp.tmpl
+++ b/third_party/WebKit/Source/bindings/templates/interface.cpp.tmpl
@@ -557,6 +557,35 @@ v8::Local<v8::FunctionTemplate> {{v8_class}}Constructor::domTemplate(v8::Isolate
   return result;
 }
 
+void {{v8_class}}Constructor::NamedConstructorAttributeGetter(
+    v8::Local<v8::Name> propertyName,
+    const v8::PropertyCallbackInfo<v8::Value>& info) {
+  v8::Local<v8::Context> creationContext = info.Holder()->CreationContext();
+  V8PerContextData* perContextData = V8PerContextData::from(creationContext);
+  if (!perContextData) {
+    // TODO(yukishiino): Return a valid named constructor even after the context is detached
+    return;
+  }
+
+  v8::Local<v8::Function> namedConstructor = perContextData->constructorForType(&{{v8_class}}Constructor::wrapperTypeInfo);
+
+  // Set the prototype of named constructors to the regular constructor.
+  auto privateProperty = V8PrivateProperty::getNamedConstructorInitialized(info.GetIsolate());
+  v8::Local<v8::Context> currentContext = info.GetIsolate()->GetCurrentContext();
+  v8::Local<v8::Value> privateValue = privateProperty.get(currentContext, namedConstructor);
+
+  if (privateValue.IsEmpty()) {
+    v8::Local<v8::Function> interface = perContextData->constructorForType(&{{v8_class}}::wrapperTypeInfo);
+    v8::Local<v8::Value> interfacePrototype = interface->Get(currentContext, v8AtomicString(info.GetIsolate(), "prototype")).ToLocalChecked();
+    bool result = namedConstructor->Set(currentContext, v8AtomicString(info.GetIsolate(), "prototype"), interfacePrototype).ToChecked();
+    if (!result)
+      return;
+    privateProperty.set(currentContext, namedConstructor, v8::True(info.GetIsolate()));
+  }
+
+  v8SetReturnValue(info, namedConstructor);
+}
+
 {% endif %}
 {% endblock %}