Internalize strings being stored into uninitialized property cells

src/lookup.cc

Index: src/lookup.cc
diff --git a/src/lookup.cc b/src/lookup.cc
index 55e9d689a118765c97256aee5d5f98a8138d3ce2..6a540de4df621f82adda771e9007fa5ac9adae40 100644
--- a/src/lookup.cc
+++ b/src/lookup.cc
@@ -289,7 +289,7 @@ Handle<Object> LookupIterator::GetDataValue() const {
 }
 
 
-void LookupIterator::WriteDataValue(Handle<Object> value) {
+Handle<Object> LookupIterator::WriteDataValue(Handle<Object> value) {
   DCHECK_EQ(DATA, state_);
   Handle<JSObject> holder = GetHolder<JSObject>();
   if (holder_map_->is_dictionary_map()) {
@@ -297,7 +297,7 @@ void LookupIterator::WriteDataValue(Handle<Object> value) {
     if (holder->IsGlobalObject()) {
       Handle<PropertyCell> cell(
           PropertyCell::cast(property_dictionary->ValueAt(dictionary_entry())));
-      PropertyCell::SetValueInferType(cell, value);
+      value = PropertyCell::SetValueInferType(cell, value);
     } else {
       property_dictionary->ValueAtPut(dictionary_entry(), *value);
     }
@@ -306,6 +306,7 @@ void LookupIterator::WriteDataValue(Handle<Object> value) {
   } else {
     DCHECK_EQ(v8::internal::CONSTANT, property_details_.type());
   }
+  return value;
 }