[serializer] do not cache resource data pointer for native source.

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index 7d2dad06243c92581f59ee662f5bd56f687eaa36..480fcfbd4fd7fa03a7786f01df310ee0bfdb55a6 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -704,6 +704,21 @@ MaybeHandle<String> Factory::NewExternalStringFromTwoByte(
   return external_string;
 }
 
+Handle<ExternalOneByteString> Factory::NewNativeSourceString(
+    const ExternalOneByteString::Resource* resource) {
+  size_t length = resource->length();
+  DCHECK_LE(length, static_cast<size_t>(String::kMaxLength));
+
+  Handle<Map> map = native_source_string_map();
+  Handle<ExternalOneByteString> external_string =
+      New<ExternalOneByteString>(map, OLD_SPACE);
+  external_string->set_length(static_cast<int>(length));
+  external_string->set_hash_field(String::kEmptyHashField);
+  external_string->set_resource(resource);
+
+  return external_string;
+}
+
 
 Handle<Symbol> Factory::NewSymbol() {
   CALL_HEAP_FUNCTION(