bind-gen: Fix the implementation of named constructors

Bug: 839389
Change-Id: I802b01943d6c6a5a178c40f516ac367d43981c82
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2145424
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758442}

third_party/blink/renderer/bindings/core/v8/generated_code_helper.cc

@@ -255,15 +255,33 @@ v8::MaybeLocal<v8::Function> CreateNamedConstructorFunction(
         v8::SideEffectType::kHasSideEffect);
     v8::Local<v8::FunctionTemplate> interface_template =
         wrapper_type_info->DomTemplate(isolate, world);
-    function_template->SetPrototypeProviderTemplate(interface_template);
-    function_template->ReadOnlyPrototype();
+    function_template->Inherit(interface_template);
     function_template->SetClassName(V8AtomicString(isolate, func_name));
     function_template->InstanceTemplate()->SetInternalFieldCount(
         kV8DefaultWrapperInternalFieldCount);
     per_isolate_data->SetInterfaceTemplate(world, callback_key,
                                            function_template);
   }
-  return function_template->GetFunction(script_state->GetContext());
+
+  v8::Local<v8::Context> context = script_state->GetContext();
+  V8PerContextData* per_context_data = V8PerContextData::From(context);
+  v8::Local<v8::Function> function;
+  if (!function_template->GetFunction(context).ToLocal(&function)) {
+    return v8::MaybeLocal<v8::Function>();
+  }
+  v8::Local<v8::Object> prototype_object =
+      per_context_data->PrototypeForType(wrapper_type_info);
+  bool did_define;
+  if (!function
+           ->DefineOwnProperty(
+               context, V8AtomicString(isolate, "prototype"), prototype_object,
+               static_cast<v8::PropertyAttribute>(v8::ReadOnly | v8::DontEnum |
+                                                  v8::DontDelete))
+           .To(&did_define)) {
+    return v8::MaybeLocal<v8::Function>();
+  }
+  CHECK(did_define);
+  return function;
 }
 
 void InstallUnscopablePropertyNames(

third_party/blink/renderer/bindings/scripts/bind_gen/interface.py

@@ -762,12 +762,14 @@ def make_check_constructor_call(cg_context):
                    "ExceptionMessages::ConstructorNotCallableAsFunction("
                    "${class_like_name}));\n"
                    "return;")),
-        CxxLikelyIfNode(
-            cond=("ConstructorMode::Current(${isolate}) == "
-                  "ConstructorMode::kWrapExistingObject"),
-            body=T("bindings::V8SetReturnValue(${info}, ${v8_receiver});\n"
-                   "return;")),
     ])
+    if not cg_context.is_named_constructor:
+        node.append(
+            CxxLikelyIfNode(
+                cond=("ConstructorMode::Current(${isolate}) == "
+                      "ConstructorMode::kWrapExistingObject"),
+                body=T("bindings::V8SetReturnValue(${info}, ${v8_receiver});\n"
+                       "return;")))
     node.accumulate(
         CodeGenAccumulator.require_include_headers([
             "third_party/blink/renderer/platform/bindings/v8_object_constructor.h",
@@ -1802,9 +1804,11 @@ static const V8PrivateProperty::SymbolKey kPrivatePropertyNamedConstructor;
 auto&& v8_private_named_constructor =
     V8PrivateProperty::GetSymbol(${isolate}, kPrivatePropertyNamedConstructor);
 v8::Local<v8::Value> v8_named_constructor;
-if (v8_private_named_constructor.GetOrUndefined(${v8_receiver})
-        .ToLocal(&v8_named_constructor) &&
-    !v8_named_constructor->IsUndefined()) {
+if (!v8_private_named_constructor.GetOrUndefined(${v8_receiver})
+         .ToLocal(&v8_named_constructor)) {
+  return;
+}
+if (!v8_named_constructor->IsUndefined()) {
   bindings::V8SetReturnValue(${info}, v8_named_constructor);
   return;
 }