Reapply descriptor array sharing.

src/handles.h

 // Copyright 2011 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 258 matching lines @@
                                                    Handle<JSObject> object);
 
 enum KeyCollectionType { LOCAL_ONLY, INCLUDE_PROTOS };
 
 // Computes the enumerable keys for a JSObject. Used for implementing
 // "for (n in object) { }".
 Handle<FixedArray> GetKeysInFixedArrayFor(Handle<JSReceiver> object,
                                           KeyCollectionType type,
                                           bool* threw);
 Handle<JSArray> GetKeysFor(Handle<JSReceiver> object, bool* threw);
+Handle<FixedArray> ReduceFixedArrayTo(Handle<FixedArray> array, int length);
 Handle<FixedArray> GetEnumPropertyKeys(Handle<JSObject> object,
                                        bool cache_result);
 
 // Computes the union of keys and return the result.
 // Used for implementing "for (n in object) { }"
 Handle<FixedArray> UnionOfKeys(Handle<FixedArray> first,
                                Handle<FixedArray> second);
 
 Handle<String> SubString(Handle<String> str,
                          int start,
@@ skipping 38 matching lines @@
   inline ~NoHandleAllocation();
  private:
   int level_;
   bool active_;
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HANDLES_H_