Missing header addressed.
diff --git a/tensorflow/core/transforms/remapper/remapping_helper.h b/tensorflow/core/transforms/remapper/remapping_helper.h
index d43537b..6f67675 100644
--- a/tensorflow/core/transforms/remapper/remapping_helper.h
+++ b/tensorflow/core/transforms/remapper/remapping_helper.h
@@ -15,6 +15,8 @@
#ifndef TENSORFLOW_CORE_TRANSFORMS_REMAPPER_REMAPPING_HELPER_H_
#define TENSORFLOW_CORE_TRANSFORMS_REMAPPER_REMAPPING_HELPER_H_
+#include <string>
+
#include "tensorflow/core/framework/types.h"
#include "tensorflow/core/transforms/utils/op_cat_helper.h"
#include "tensorflow/core/transforms/utils/utils.h"