gfe-relnote: Use HandshakerDelegateInterface in QUIC handshakers. Abstract keys installation, keys discarding, default encryption level change and mark handshake complete to HandshakerDelegateInterface. Protected by gfe2_reloadable_flag_quic_use_handshaker_delegate.

The final goal is remove session pointer from handshakers.

PiperOrigin-RevId: 282826263
Change-Id: I9b379ccfcebd174df1850f7df45069d388460173
diff --git a/quic/quic_transport/quic_transport_client_session.h b/quic/quic_transport/quic_transport_client_session.h
index 4df008c..5872bf1 100644
--- a/quic/quic_transport/quic_transport_client_session.h
+++ b/quic/quic_transport/quic_transport_client_session.h
@@ -81,6 +81,7 @@
   }
 
   void OnCryptoHandshakeEvent(CryptoHandshakeEvent event) override;
+  void SetDefaultEncryptionLevel(EncryptionLevel level) override;
 
   // Return the earliest incoming stream that has been received by the session
   // but has not been accepted.  Returns nullptr if there are no incoming