Fix a bug where QUIC ack frames were not bundled with crypto stream

net/quic/quic_connection.h

Index: net/quic/quic_connection.h
diff --git a/net/quic/quic_connection.h b/net/quic/quic_connection.h
index 689d595efb7ccdfde7d1dd6471d4002dba49a83e..fec6c6882e579b033e43a916924a0596672c69d7 100644
--- a/net/quic/quic_connection.h
+++ b/net/quic/quic_connection.h
@@ -389,10 +389,6 @@ class NET_EXPORT_PRIVATE QuicConnection
     return connection_close_packet_.release();
   }
 
-  // Flush any queued frames immediately.  Preserves the batch write mode and
-  // does nothing if there are no pending frames.
-  void Flush();
-
   // Returns true if the underlying UDP socket is writable, there is
   // no queued data and the connection is not congestion-control
   // blocked.