Change JSObject elements to be of type FixedArrayBase

src/objects.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 617 matching lines @@
   inline bool name();                  \
   inline void set_##name(bool value);  \
 
 
 #define DECL_ACCESSORS(name, type)                                      \
   inline type* name();                                                  \
   inline void set_##name(type* value,                                   \
                          WriteBarrierMode mode = UPDATE_WRITE_BARRIER); \
 
 
+class DictionaryElementsAccessor;
 class ElementsAccessor;
+class FixedArrayBase;
+class ObjectVisitor;
 class StringStream;
-class ObjectVisitor;
-class DictionaryElementsAccessor;
 
 struct ValueInfo : public Malloced {
   ValueInfo() : type(FIRST_TYPE), ptr(NULL), str(NULL), number(0) { }
   InstanceType type;
   Object* ptr;
   const char* str;
   double number;
 };
 
 
@@ skipping 834 matching lines @@
   // elements array can have one of three maps in this mode:
   // fixed_array_map, non_strict_arguments_elements_map or
   // fixed_cow_array_map (for copy-on-write arrays). In the latter case
   // the elements array may be shared by a few objects and so before
   // writing to any element the array must be copied. Use
   // EnsureWritableFastElements in this case.
   //
   // In the slow mode the elements is either a NumberDictionary, an
   // ExternalArray, or a FixedArray parameter map for a (non-strict)
   // arguments object.
-  DECL_ACCESSORS(elements, HeapObject)
+  DECL_ACCESSORS(elements, FixedArrayBase)
   inline void initialize_elements();
   MUST_USE_RESULT inline MaybeObject* ResetElements();
   inline ElementsKind GetElementsKind();
   inline ElementsAccessor* GetElementsAccessor();
   inline bool HasFastElements();
   inline bool HasFastDoubleElements();
   inline bool HasDictionaryElements();
   inline bool HasExternalPixelElements();
   inline bool HasExternalArrayElements();
   inline bool HasExternalByteElements();
@@ skipping 5804 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_