Fix issue with Array.concat not preserving holes in the

src/objects.h

 // Copyright 2006-2008 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 1957 matching lines @@
   // Returns the number of enumerable elements in the dictionary.
   int NumberOfEnumElements();
 
   // Copies keys to preallocated fixed array.
   void CopyKeysTo(FixedArray* storage, PropertyAttributes filter);
   // Copies enumerable keys to preallocated fixed array.
   void CopyEnumKeysTo(FixedArray* storage, FixedArray* sort_array);
   // Fill in details for properties into storage.
   void CopyKeysTo(FixedArray* storage);
 
-  // Returns the value at entry.
-  static int ValueIndexFor(int entry) { return EntryToIndex(entry)+1; }
-
   // For transforming properties of a JSObject.
   Object* TransformPropertiesToFastFor(JSObject* obj,
                                        int unused_property_fields);
 
   // If slow elements are required we will never go back to fast-case
   // for the elements kept in this dictionary.  We require slow
   // elements if an element has been added at an index larger than
   // kRequiresSlowElementsLimit.
   inline bool requires_slow_elements();
 
@@ skipping 2130 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_