A change in the way we place TransitionElementKinds in the tree.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 2881ec8fe41ca3d686a6ef86f2c4e84f22990b1b..a7d8254990ee4fbcd8f175895afc6764dc72c276 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -4694,6 +4694,9 @@ class Code: public HeapObject {
 };
 
 
+Map* FindClosestElementsTransition(Map* map, ElementsKind to_kind);
+
+
 // All heap objects have a Map that describes their structure.
 //  A Map contains information about:
 //  - Size information about the object
@@ -4872,6 +4875,7 @@ class Map: public HeapObject {
   MUST_USE_RESULT inline MaybeObject* AddTransition(String* key,
                                                     Map* target,
                                                     SimpleTransitionFlag flag);
+  MaybeObject* AddMissingElementsTransitions(ElementsKind to_kind);
   DECL_ACCESSORS(transitions, TransitionArray)
   inline void ClearTransitions(Heap* heap,
                                WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
@@ -5113,7 +5117,6 @@ class Map: public HeapObject {
   // elements_kind that's found in |candidates|, or null handle if no match is
   // found at all.
   Handle<Map> FindTransitionedMap(MapHandleList* candidates);
-  Map* FindTransitionedMap(MapList* candidates);
 
   // Zaps the contents of backing data structures. Note that the
   // heap verifier (i.e. VerifyMarkingVisitor) relies on zapping of objects