[ic] Use validity cells to protect keyed element stores against object's prototype chain modificati…

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index 3c6eb250ee2329ad79b7294dad6bc34b5eccd33f..1ae768ba0e50566c6540d1cc7a9a806486192a56 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -103,6 +103,14 @@ Handle<PrototypeInfo> Factory::NewPrototypeInfo() {
   return result;
 }
 
+Handle<Tuple2> Factory::NewTuple2(Handle<Object> value1,
+                                  Handle<Object> value2) {
+  Handle<Tuple2> result = Handle<Tuple2>::cast(NewStruct(TUPLE2_TYPE));
+  result->set_value1(*value1);
+  result->set_value2(*value2);
+  return result;
+}
+
 Handle<Tuple3> Factory::NewTuple3(Handle<Object> value1, Handle<Object> value2,
                                   Handle<Object> value3) {
   Handle<Tuple3> result = Handle<Tuple3>::cast(NewStruct(TUPLE3_TYPE));