Gate absl::Cord usage on `#if defined(TF_CORD_SUPPORT)`

PiperOrigin-RevId: 391622882
Change-Id: I5cff9eb66efa7bee8cebfddb41e5aa10a6638364
diff --git a/tensorflow/core/lib/io/record_writer.h b/tensorflow/core/lib/io/record_writer.h
index 8072dab..5d97536 100644
--- a/tensorflow/core/lib/io/record_writer.h
+++ b/tensorflow/core/lib/io/record_writer.h
@@ -98,7 +98,9 @@
   // "header[0,kHeaderSize-1]".  The record-header is based on data[0, n-1].
   inline static void PopulateHeader(char* header, const char* data, size_t n);
 
+#if defined(TF_CORD_SUPPORT)
   inline static void PopulateHeader(char* header, const absl::Cord& data);
+#endif
 
   // Utility method to populate TFRecord footers.  Populates record-footer in
   // "footer[0,kFooterSize-1]".  The record-footer is based on data[0, n-1].