Make order of addition the primary order of descriptor arrays.

src/transitions.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 35 matching lines @@
 // [2] Smi(0) or elements transition map
 // [3] Smi(0) or fixed array of prototype transitions
 // [4] First transition
 // [length() - kTransitionSize] Last transition
 class TransitionArray: public FixedArray {
  public:
   // Accessors for fetching instance transition at transition number.
   inline String* GetKey(int transition_number);
   inline void SetKey(int transition_number, String* value);
   inline Object** GetKeySlot(int transition_number);
+  int GetSortedKeyIndex(int transition_number) { return transition_number; }
+
+  String* GetSortedKey(int transition_number) {
+    return GetKey(transition_number);
+  }
 
   inline Map* GetTarget(int transition_number);
   inline void SetTarget(int transition_number, Map* target);
 
   inline PropertyDetails GetTargetDetails(int transition_number);
 
   inline Map* elements_transition();
   inline void set_elements_transition(
       Map* target,
       WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
@@ skipping 110 matching lines @@
                   Map* target,
                   const WhitenessWitness&);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(TransitionArray);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TRANSITIONS_H_