Add missing FastElements check.

src/elements-kind.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 181 matching lines @@
 }
 
 
 ElementsKind GetNextMoreGeneralFastElementsKind(ElementsKind elements_kind,
                                                 bool allow_only_packed);
 
 
 inline bool CanTransitionToMoreGeneralFastElementsKind(
     ElementsKind elements_kind,
     bool allow_only_packed) {
-  return elements_kind != TERMINAL_FAST_ELEMENTS_KIND &&
-      (!allow_only_packed || elements_kind != FAST_ELEMENTS);
+  return IsFastElementsKind(elements_kind) &&
+      (elements_kind != TERMINAL_FAST_ELEMENTS_KIND &&
+       (!allow_only_packed || elements_kind != FAST_ELEMENTS));
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ELEMENTS_KIND_H_