Make index translate/inobject only rely on the map.

src/property.h

Index: src/property.h
diff --git a/src/property.h b/src/property.h
index 0f78ba478ec8512e8d94fd57a502a42a470c582a..88f1acc0c987661c57ece20fe0ef6c43399f9f34 100644
--- a/src/property.h
+++ b/src/property.h
@@ -150,16 +150,16 @@ class PropertyIndex {
     return value();
   }
 
-  bool is_inobject(Handle<JSObject> holder) {
+  bool is_inobject(Map* map) {
     if (is_header_index()) return true;
-    return field_index() < holder->map()->inobject_properties();
+    return field_index() < map->inobject_properties();
   }
 
-  int translate(Handle<JSObject> holder) {
+  int translate(Map* map) {
     if (is_header_index()) return header_index();
-    int index = field_index() - holder->map()->inobject_properties();
+    int index = field_index() - map->inobject_properties();
     if (index >= 0) return index;
-    return index + holder->map()->instance_size() / kPointerSize;
+    return index + map->instance_size() / kPointerSize;
   }
 
  private: