Moving the WhitenessWitness back to DescriptorArray.

src/transitions.cc

Index: src/transitions.cc
diff --git a/src/transitions.cc b/src/transitions.cc
index 0ea58c7d5f530164611c5292658ac6a91d275bc0..199fcc2c9838fb0691bbedd4c00e1dd7bd27bb3e 100644
--- a/src/transitions.cc
+++ b/src/transitions.cc
@@ -58,14 +58,12 @@ MaybeObject* TransitionArray::Allocate(int number_of_transitions,
 }
 
 
-void TransitionArray::CopyFrom(TransitionArray* origin,
-                               int origin_transition,
-                               int target_transition,
-                               const WhitenessWitness& witness) {
-  Set(target_transition,
-      origin->GetKey(origin_transition),
-      origin->GetTarget(origin_transition),
-      witness);
+void TransitionArray::NoIncrementalWriteBarrierCopyFrom(TransitionArray* origin,
+                                                        int origin_transition,
+                                                        int target_transition) {
+  NoIncrementalWriteBarrierSet(target_transition,
+                               origin->GetKey(origin_transition),
+                               origin->GetTarget(origin_transition));
 }
 
 
@@ -84,9 +82,7 @@ MaybeObject* TransitionArray::NewWith(
   MaybeObject* maybe_array = TransitionArray::Allocate(1, descriptors_pointer);
   if (!maybe_array->To(&result)) return maybe_array;
 
-  FixedArray::WhitenessWitness witness(result);
-
-  result->Set(0, name, target, witness);
+  result->NoIncrementalWriteBarrierSet(0, name, target);
   result->set_back_pointer_storage(back_pointer);
   return result;
 }
@@ -113,26 +109,28 @@ MaybeObject* TransitionArray::CopyInsert(String* name, Map* target) {
     result->SetPrototypeTransitions(GetPrototypeTransitions());
   }
 
-  FixedArray::WhitenessWitness witness(result);
-
   if (insertion_index != kNotFound) {
     for (int i = 0; i < number_of_transitions; ++i) {
-      if (i != insertion_index) result->CopyFrom(this, i, i, witness);
+      if (i != insertion_index) {
+        result->NoIncrementalWriteBarrierCopyFrom(this, i, i);
+      }
     }
-    result->Set(insertion_index, name, target, witness);
+    result->NoIncrementalWriteBarrierSet(insertion_index, name, target);
     return result;
   }
 
   insertion_index = 0;
   for (; insertion_index < number_of_transitions; ++insertion_index) {
     if (InsertionPointFound(GetKey(insertion_index), name)) break;
-    result->CopyFrom(this, insertion_index, insertion_index, witness);
+    result->NoIncrementalWriteBarrierCopyFrom(
+        this, insertion_index, insertion_index);
   }
 
-  result->Set(insertion_index, name, target, witness);
+  result->NoIncrementalWriteBarrierSet(insertion_index, name, target);
 
   for (; insertion_index < number_of_transitions; ++insertion_index) {
-    result->CopyFrom(this, insertion_index, insertion_index + 1, witness);
+    result->NoIncrementalWriteBarrierCopyFrom(
+        this, insertion_index, insertion_index + 1);
   }
 
   result->set_back_pointer_storage(back_pointer_storage());