Improve hard-coded QuicSimpleServerStream's push promise id.

In IETF world, HTTP/3 static unidirectional streams are not guaranteed to be created at initialization. So we need to explicitly adjust highest_push_promise_id_ when a new H/3 static stream is created.

gfe-relnote: v99 change only, not protected.
PiperOrigin-RevId: 262976660
Change-Id: I3182356ae6560486b5677abdc73846f452598b24
diff --git a/quic/tools/quic_simple_server_session.h b/quic/tools/quic_simple_server_session.h
index 12748ad..d485e7c 100644
--- a/quic/tools/quic_simple_server_session.h
+++ b/quic/tools/quic_simple_server_session.h
@@ -102,6 +102,8 @@
     return quic_simple_server_backend_;
   }
 
+  void MaybeInitializeHttp3UnidirectionalStreams() override;
+
  private:
   friend class test::QuicSimpleServerSessionPeer;