diff --git a/quic/core/tls_client_handshaker.cc b/quic/core/tls_client_handshaker.cc
index 30a9ac4..aed628e 100644
--- a/quic/core/tls_client_handshaker.cc
+++ b/quic/core/tls_client_handshaker.cc
@@ -216,6 +216,9 @@
     params.google_quic_params->SetStringPiece(kUAID, user_agent_id_);
   }
 
+  // Notify QuicConnectionDebugVisitor.
+  session()->connection()->OnTransportParametersSent(params);
+
   std::vector<uint8_t> param_bytes;
   return SerializeTransportParameters(session()->connection()->version(),
                                       params, &param_bytes) &&
@@ -244,6 +247,10 @@
     return false;
   }
 
+  // Notify QuicConnectionDebugVisitor.
+  session()->connection()->OnTransportParametersReceived(
+      *received_transport_params_);
+
   // When interoperating with non-Google implementations that do not send
   // the version extension, set it to what we expect.
   if (received_transport_params_->version == 0) {