Add a callback that notifies the QuicTransportClientSession visitor when the session is ready.

Also add a bit of extra defense in depth for ALPN checks.

gfe-relnote: n/a (not used in production)
PiperOrigin-RevId: 284658419
Change-Id: Ic665263a024821e529c564e7c8b86d362f9991a8
diff --git a/quic/quic_transport/quic_transport_integration_test.cc b/quic/quic_transport/quic_transport_integration_test.cc
index 1695a19..f5c804d 100644
--- a/quic/quic_transport/quic_transport_integration_test.cc
+++ b/quic/quic_transport/quic_transport_integration_test.cc
@@ -205,6 +205,7 @@
 TEST_F(QuicTransportIntegrationTest, SuccessfulHandshake) {
   CreateDefaultEndpoints("/discard");
   WireUpEndpoints();
+  EXPECT_CALL(*client_->visitor(), OnSessionReady());
   RunHandshake();
   EXPECT_TRUE(client_->session()->IsSessionReady());
   EXPECT_TRUE(server_->session()->IsSessionReady());