Don't create new maps in CurrentMapForDeprecated.

src/ast.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 260 matching lines @@
   SmallMapList(int capacity, Zone* zone) : list_(capacity, zone) {}
 
   void Reserve(int capacity, Zone* zone) { list_.Reserve(capacity, zone); }
   void Clear() { list_.Clear(); }
   void Sort() { list_.Sort(); }
 
   bool is_empty() const { return list_.is_empty(); }
   int length() const { return list_.length(); }
 
   void AddMapIfMissing(Handle<Map> map, Zone* zone) {
-    map = Map::CurrentMapForDeprecated(map);
+    Map* updated = map->CurrentMapForDeprecated();
+    if (updated == NULL) return;
+    map = Handle<Map>(updated);
     for (int i = 0; i < length(); ++i) {
       if (at(i).is_identical_to(map)) return;
     }
     Add(map, zone);
   }
 
   void Add(Handle<Map> handle, Zone* zone) {
     ASSERT(!handle->is_deprecated());
     list_.Add(handle.location(), zone);
   }
@@ skipping 2772 matching lines @@
  private:
   Isolate* isolate_;
   Zone* zone_;
   Visitor visitor_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_