Mark maps having a hidden prototype rather than maps of hidden prototypes.

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 566 matching lines @@
   // Down from here is only valid for API functions that can be used as a
   // constructor (don't set the "remove prototype" flag).
 
   Handle<Map> map(result->initial_map());
 
   // Mark as undetectable if needed.
   if (obj->undetectable()) {
     map->set_is_undetectable();
   }
 
-  // Mark as hidden for the __proto__ accessor if needed.
-  if (obj->hidden_prototype()) {
-    map->set_is_hidden_prototype();
-  }
-
   // Mark as needs_access_check if needed.
   if (obj->needs_access_check()) {
     map->set_is_access_check_needed(true);
   }
 
   // Set interceptor information in the map.
   if (!obj->named_property_handler()->IsUndefined()) {
     map->set_has_named_interceptor();
   }
   if (!obj->indexed_property_handler()->IsUndefined()) {
     map->set_has_indexed_interceptor();
   }
 
   // Mark instance as callable in the map.
   if (!obj->instance_call_handler()->IsUndefined()) {
     map->set_is_callable();
     map->set_is_constructor(true);
   }
 
   DCHECK(result->shared()->IsApiFunction());
   return result;
 }
 
 }  // namespace internal
 }  // namespace v8