Allow immutable prototype templates to inherit

src/api-natives.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/api-natives.h"
 
 #include "src/api.h"
 #include "src/isolate-inl.h"
 #include "src/lookup.h"
 #include "src/messages.h"
@@ skipping 419 matching lines @@
           InstantiateFunction(
               isolate, handle(FunctionTemplateInfo::cast(parent), isolate)),
           JSFunction);
       // TODO(dcarney): decide what to do here.
       Handle<Object> parent_prototype;
       ASSIGN_RETURN_ON_EXCEPTION(
           isolate, parent_prototype,
           JSObject::GetProperty(parent_instance,
                                 isolate->factory()->prototype_string()),
           JSFunction);
-      MAYBE_RETURN(JSObject::SetPrototype(prototype, parent_prototype, false,
-                                          Object::THROW_ON_ERROR),
-                   MaybeHandle<JSFunction>());
+      JSObject::ForceSetPrototype(prototype, parent_prototype);
     }
   }
   Handle<JSFunction> function = ApiNatives::CreateApiFunction(
       isolate, data, prototype, ApiNatives::JavaScriptObjectType);
   if (!name.is_null() && name->IsString()) {
     function->shared()->set_name(*name);
   }
   if (serial_number) {
     // Cache the function.
     CacheTemplateInstantiation(isolate, serial_number, function);
@@ skipping 223 matching lines @@
   if (!obj->instance_call_handler()->IsUndefined(isolate)) {
     map->set_is_callable();
     map->set_is_constructor(true);
   }
 
   return result;
 }
 
 }  // namespace internal
 }  // namespace v8