In-place shrinking of descriptor arrays with non-live transitions.

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 33cbb8149f7dc41b8499df044126c19c939603f6..d15beb29b976be5eebbb9863bd8a81d826260217 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -2193,13 +2193,13 @@ void Genesis::TransferNamedProperties(Handle<JSObject> from,
         }
         case MAP_TRANSITION:
         case CONSTANT_TRANSITION:
-        case NULL_DESCRIPTOR:
           // Ignore non-properties.
           break;
         case NORMAL:
           // Do not occur since the from object has fast properties.
         case HANDLER:
         case INTERCEPTOR:
+        case NONEXISTENT:
           // No element in instance descriptors have proxy or interceptor type.
           UNREACHABLE();
           break;