Better support for 'polymorphic' JS and external arrays

src/list.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 146 matching lines @@
   // Inlined implementation of ResizeAdd, shared by inlined and
   // non-inlined versions of ResizeAdd.
   void ResizeAddInternal(const T& element);
 
   // Resize the list.
   void Resize(int new_capacity);
 
   DISALLOW_COPY_AND_ASSIGN(List);
 };
 
+class Map;
+class Code;
+typedef List<Map*> MapList;
+typedef List<Code*> CodeList;
+
 } }  // namespace v8::internal
 
 #endif  // V8_LIST_H_