Add IsResumption method to QUIC client handshakers

gfe-relnote: no behavior change: adding unused method
PiperOrigin-RevId: 279141655
Change-Id: Icfe08baf904b37a702c73c071334b11bb6cf2234
diff --git a/quic/core/tls_client_handshaker.cc b/quic/core/tls_client_handshaker.cc
index 749d15f..2056953 100644
--- a/quic/core/tls_client_handshaker.cc
+++ b/quic/core/tls_client_handshaker.cc
@@ -197,6 +197,12 @@
   return 0;
 }
 
+bool TlsClientHandshaker::IsResumption() const {
+  QUIC_BUG_IF(!handshake_confirmed_);
+  // We don't support resumption (yet).
+  return false;
+}
+
 int TlsClientHandshaker::num_scup_messages_received() const {
   // SCUP messages aren't sent or received when using the TLS handshake.
   return 0;