Use new connection ID in connection migration on the client side.

Code is protected by connection_migration_use_new_cid_, which will be enabled by reloadable flag in follow up CL once the feature is complete.

PiperOrigin-RevId: 369297584
Change-Id: Ie5ce5e2ac987beb0f04f121227633e5934ed2210
diff --git a/quic/test_tools/quic_connection_peer.h b/quic/test_tools/quic_connection_peer.h
index 174e2c3..df2a823 100644
--- a/quic/test_tools/quic_connection_peer.h
+++ b/quic/test_tools/quic_connection_peer.h
@@ -199,12 +199,18 @@
 
   static void EnableMultipleConnectionIdSupport(QuicConnection* connection);
 
+  // Remove this method once the boolean is enabled via reloadable flag.
+  static void EnableConnectionMigrationUseNewCID(QuicConnection* connection);
+
   static void ResetPeerIssuedConnectionIdManager(QuicConnection* connection);
 
   static QuicConnection::PathState* GetDefaultPath(QuicConnection* connection);
 
   static QuicConnection::PathState* GetAlternativePath(
       QuicConnection* connection);
+
+  static void RetirePeerIssuedConnectionIdsNoLongerOnPath(
+      QuicConnection* connection);
 };
 
 }  // namespace test