Avoid using a register for constant external array indices.

src/lithium.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 570 matching lines @@
   }
 
  private:
   inline void AdvanceToOuter() {
     current_iterator_ = ShallowIterator(current_iterator_.env()->outer());
   }
 
   ShallowIterator current_iterator_;
 };
 
+
+int ExternalArrayTypeToShiftSize(ExternalArrayType type);
+
+
 } }  // namespace v8::internal
 
 #endif  // V8_LITHIUM_H_