Roll forward to cl/314747126

Signed-off-by: Alexey Polyudov <apolyudov@google.com>
Change-Id: Ie19e006429b138b3768e97dae971a43fdc5ef8bf

cpp/core/internal/mediums/utils.h

@@ -35,6 +35,8 @@ class Utils {
   static ConstPtr<ByteArray> legacySha256HashOnlyForPrinting(
       Ptr<HashUtils> hash_utils, ConstPtr<ByteArray> source, size_t length);
 
+  static ConstPtr<ByteArray> generateRandomBytes(size_t length);
+
  private:
   static std::string bytesToPrintableHexString(ConstPtr<ByteArray> bytes);
 };