Keep prototype maps in dictionary mode until ICs see them

src/messages.cc

Index: src/messages.cc
diff --git a/src/messages.cc b/src/messages.cc
index c9b585405af265b07b0481e83dfb65e1182bf37a..86d0277f2afcc4bc7b2751399b31805c5eeaf252 100644
--- a/src/messages.cc
+++ b/src/messages.cc
@@ -283,9 +283,8 @@ Handle<Object> CallSite::GetMethodName() {
 
   HandleScope outer_scope(isolate_);
   Handle<Object> result;
-  for (PrototypeIterator iter(isolate_, obj,
-                              PrototypeIterator::START_AT_RECEIVER);
-       !iter.IsAtEnd(); iter.Advance()) {
+  for (PrototypeIterator iter(isolate_, obj, kStartAtReceiver); !iter.IsAtEnd();
+       iter.Advance()) {
     Handle<Object> current = PrototypeIterator::GetCurrent(iter);
     if (!current->IsJSObject()) break;
     Handle<JSObject> current_obj = Handle<JSObject>::cast(current);