1 files changed, 7 insertions, 0 deletions
diff --git a/src/google/protobuf/unknown_field_set.cc b/src/google/protobuf/unknown_field_set.cc
index 8ee99d48..bca3fbf8 100644
--- a/src/google/protobuf/unknown_field_set.cc
+++ b/src/google/protobuf/unknown_field_set.cc
@@ -39,6 +39,7 @@
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/io/zero_copy_stream.h>
 #include <google/protobuf/io/zero_copy_stream_impl.h>
+#include <google/protobuf/metadata.h>
 #include <google/protobuf/wire_format.h>
 #include <google/protobuf/stubs/stl_util.h>
 
@@ -116,6 +117,12 @@ void UnknownFieldSet::MergeFromAndDestroy(UnknownFieldSet* other) {
   other->fields_ = NULL;
 }
 
+void UnknownFieldSet::MergeToInternalMetdata(
+    const UnknownFieldSet& other,
+    internal::InternalMetadataWithArena* metadata) {
+  metadata->mutable_unknown_fields()->MergeFrom(other);
+}
+
 int UnknownFieldSet::SpaceUsedExcludingSelf() const {
   if (fields_ == NULL) return 0;