Treat the builtins object like other global objects (with...

src/objects.h

Index: src/objects.h
===================================================================
--- src/objects.h	(revision 2317)
+++ src/objects.h	(working copy)
@@ -3059,6 +3059,9 @@
   // [global receiver]: the global receiver object of the context
   DECL_ACCESSORS(global_receiver, JSObject)
 
+  // Retrieve the property cell used to store a property.
+  Object* GetPropertyCell(LookupResult* result);
+
   // Casting.
   static inline GlobalObject* cast(Object* obj);
 
@@ -3079,9 +3082,6 @@
 class JSGlobalObject: public GlobalObject {
  public:
 
-  // Retrieve the property cell used to store a property.
-  Object* GetPropertyCell(LookupResult* result);
-
   // Casting.
   static inline JSGlobalObject* cast(Object* obj);