Increase MASQUE server max packet length to 1350

This allows interop with other clients that only send 1200-byte INITIAL packets. This code is not used in production.

PiperOrigin-RevId: 360728363
Change-Id: I63ee635e957549bebcdb6a6b3d54226ec8e1a325

quic/masque/masque_server_session.cc

diff --git a/quic/masque/masque_server_session.cc b/quic/masque/masque_server_session.cc
index 9b291a7..242dcbe 100644
--- a/quic/masque/masque_server_session.cc
+++ b/quic/masque/masque_server_session.cc
@@ -97,6 +97,11 @@
       epoll_server_(epoll_server),
       compression_engine_(this),
       masque_mode_(masque_mode) {
+  // Artificially increase the max packet length to 1350 to ensure we can fit
+  // QUIC packets inside DATAGRAM frames.
+  // TODO(b/181606597) Remove this workaround once we use PMTUD.
+  connection->SetMaxPacketLength(kDefaultMaxPacketSize);
+
   masque_server_backend_->RegisterBackendClient(connection_id(), this);
   QUICHE_DCHECK_NE(epoll_server_, nullptr);
 }