Reapply descriptor array sharing.

src/property.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 50 matching lines @@
   PropertyDetails GetDetails() { return details_; }
 
 #ifdef OBJECT_PRINT
   void Print(FILE* out);
 #endif
 
   void SetEnumerationIndex(int index) {
     details_ = PropertyDetails(details_.attributes(), details_.type(), index);
   }
 
-  void SetSortedKey(int index) { details_ = details_.set_pointer(index); }
+  void SetSortedKeyIndex(int index) { details_ = details_.set_pointer(index); }
 
  private:
   String* key_;
   Object* value_;
   PropertyDetails details_;
 
  protected:
   Descriptor() : details_(Smi::FromInt(0)) {}
 
   void Init(String* key, Object* value, PropertyDetails details) {
@@ skipping 295 matching lines @@
     if (lookup_type_ == DESCRIPTOR_TYPE) {
       return GetValueFromMap(holder()->map());
     }
     // In the dictionary case, the data is held in the value field.
     ASSERT(lookup_type_ == DICTIONARY_TYPE);
     return holder()->GetNormalizedProperty(this);
   }
 
   Object* GetValueFromMap(Map* map) const {
     ASSERT(lookup_type_ == DESCRIPTOR_TYPE);
+    ASSERT(number_ < map->NumberOfOwnDescriptors());
     return map->instance_descriptors()->GetValue(number_);
   }
 
   void Iterate(ObjectVisitor* visitor);
 
  private:
   Isolate* isolate_;
   LookupResult* next_;
 
   // Where did we find the result;
@@ skipping 10 matching lines @@
   JSReceiver* holder_;
   int number_;
   bool cacheable_;
   PropertyDetails details_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_PROPERTY_H_