Revert of Replace ad-hoc weakness in transition array with WeakCell.

src/transitions-inl.h

Index: src/transitions-inl.h
diff --git a/src/transitions-inl.h b/src/transitions-inl.h
index 870c8e7c0696a58400173c4dd056c34baca2e42e..f31eff96ba19e6e8e1dca0f1a4b3ee0c7c654a53 100644
--- a/src/transitions-inl.h
+++ b/src/transitions-inl.h
@@ -47,12 +47,6 @@
 }
 
 
-Object** TransitionArray::GetTargetSlot(int transition_number) {
-  DCHECK(transition_number < number_of_transitions());
-  return RawFieldOfElementAt(ToTargetIndex(transition_number));
-}
-
-
 Name* TransitionArray::GetKey(int transition_number) {
   DCHECK(transition_number < number_of_transitions());
   return Name::cast(get(ToKeyIndex(transition_number)));
@@ -77,8 +71,7 @@
 
 Map* TransitionArray::GetTarget(int transition_number) {
   DCHECK(transition_number < number_of_transitions());
-  WeakCell* cell = GetTargetCell(transition_number);
-  return Map::cast(cell->value());
+  return Map::cast(get(ToTargetIndex(transition_number)));
 }
 
 
@@ -93,13 +86,7 @@
 }
 
 
-WeakCell* TransitionArray::GetTargetCell(int transition_number) {
-  DCHECK(transition_number < number_of_transitions());
-  return WeakCell::cast(get(ToTargetIndex(transition_number)));
-}
-
-
-void TransitionArray::SetTargetCell(int transition_number, WeakCell* value) {
+void TransitionArray::SetTarget(int transition_number, Map* value) {
   DCHECK(transition_number < number_of_transitions());
   set(ToTargetIndex(transition_number), value);
 }
@@ -171,9 +158,13 @@
 }
 
 
-void TransitionArray::Set(int transition_number, Name* key, WeakCell* target) {
-  set(ToKeyIndex(transition_number), key);
-  set(ToTargetIndex(transition_number), target);
+void TransitionArray::NoIncrementalWriteBarrierSet(int transition_number,
+                                                   Name* key,
+                                                   Map* target) {
+  FixedArray::NoIncrementalWriteBarrierSet(
+      this, ToKeyIndex(transition_number), key);
+  FixedArray::NoIncrementalWriteBarrierSet(
+      this, ToTargetIndex(transition_number), target);
 }