Support datagrams in QuicTransport.

gfe-relnote: n/a (no functional change to production code)
PiperOrigin-RevId: 288493541
Change-Id: I6d2a791ae062701ad4b9fb650ab267566373675f
diff --git a/quic/test_tools/quic_test_utils.h b/quic/test_tools/quic_test_utils.h
index faa505d..15d8111 100644
--- a/quic/test_tools/quic_test_utils.h
+++ b/quic/test_tools/quic_test_utils.h
@@ -1251,6 +1251,10 @@
                           quiche::QuicheStringPiece message_data,
                           QuicMemSliceStorage* storage);
 
+// Creates a MemSlice using a singleton trivial buffer allocator.  Performs a
+// copy.
+QuicMemSlice MemSliceFromString(quiche::QuicheStringPiece data);
+
 // Used to compare ReceivedPacketInfo.
 MATCHER_P(ReceivedPacketInfoEquals, info, "") {
   return info.ToString() == arg.ToString();