Add object hidden properties to heap snapshot

src/objects.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2719 matching lines @@
   // Enqueue change record for Object.observe. May cause GC.
   static void EnqueueChangeRecord(Handle<JSObject> object,
                                   const char* type,
                                   Handle<Name> name,
                                   Handle<Object> old_value);
 
  private:
   friend class DictionaryElementsAccessor;
   friend class JSReceiver;
   friend class Object;
+  friend class V8HeapExplorer;
 
   static void UpdateAllocationSite(Handle<JSObject> object,
                                    ElementsKind to_kind);
   MUST_USE_RESULT MaybeObject* UpdateAllocationSite(ElementsKind to_kind);
 
   // Used from Object::GetProperty().
   static Handle<Object> GetPropertyWithFailedAccessCheck(
       Handle<JSObject> object,
       Handle<Object> receiver,
       LookupResult* result,
@@ skipping 8019 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_