Don't perform access checks for internally used properties

src/lookup-inl.h

 // Copyright 2014 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.
 
 #ifndef V8_LOOKUP_INL_H_
 #define V8_LOOKUP_INL_H_
 
 #include "src/lookup.h"
 
 namespace v8 {
@@ skipping 20 matching lines @@
 }
 
 
 LookupIterator::State LookupIterator::LookupInHolder(Map* map,
                                                      JSReceiver* holder) {
   STATIC_ASSERT(INTERCEPTOR == BEFORE_PROPERTY);
   DisallowHeapAllocation no_gc;
   switch (state_) {
     case NOT_FOUND:
       if (map->IsJSProxyMap()) return JSPROXY;
-      if (map->is_access_check_needed()) return ACCESS_CHECK;
+      if (map->is_access_check_needed() &&
+          !isolate_->IsInternallyUsedPropertyName(name_)) {
+        return ACCESS_CHECK;
+      }
     // Fall through.
     case ACCESS_CHECK:
       if (check_interceptor() && map->has_named_interceptor()) {
         return INTERCEPTOR;
       }
     // Fall through.
     case INTERCEPTOR:
       if (map->is_dictionary_map()) {
         NameDictionary* dict = JSObject::cast(holder)->property_dictionary();
         number_ = dict->FindEntry(name_);
@@ skipping 24 matching lines @@
     case TRANSITION:
       UNREACHABLE();
   }
   UNREACHABLE();
   return state_;
 }
 }
 }  // namespace v8::internal
 
 #endif  // V8_LOOKUP_INL_H_