Support for global var shortcuts in script contexts.

src/heap/heap.h

Index: src/heap/heap.h
diff --git a/src/heap/heap.h b/src/heap/heap.h
index a57a46d85edd6c351bc66be96d192271b6be3578..6f88ab23bc6daf292b61949001f80e598da3ba9d 100644
--- a/src/heap/heap.h
+++ b/src/heap/heap.h
@@ -192,6 +192,7 @@ namespace internal {
   V(ArrayList, retained_maps, RetainedMaps)                                    \
   V(WeakHashTable, weak_object_to_code_table, WeakObjectToCodeTable)           \
   V(PropertyCell, array_protector, ArrayProtector)                             \
+  V(PropertyCell, empty_property_cell, EmptyPropertyCell)                      \
   V(Object, weak_stack_trace_list, WeakStackTraceList)
 
 // Entries in this list are limited to Smis and are not visited during GC.