gfe-relnote: Allow GFE to perform initial cwnd up and down experiment. Protected by --gfe2_reloadable_flag_quic_gfe_selected_initial_cwnd_experiments.

The minimum cwnd is 10, and the default enabled up and down experiment is 25%.

PiperOrigin-RevId: 248124804
Change-Id: Ie21685f8e35946eaa499dab935b154b928af7318
diff --git a/quic/core/quic_sent_packet_manager.h b/quic/core/quic_sent_packet_manager.h
index 04fab58..3df874d 100644
--- a/quic/core/quic_sent_packet_manager.h
+++ b/quic/core/quic_sent_packet_manager.h
@@ -130,7 +130,9 @@
 
   // Notify the sent packet manager of an external network measurement or
   // prediction for either |bandwidth| or |rtt|; either can be empty.
-  void AdjustNetworkParameters(QuicBandwidth bandwidth, QuicTime::Delta rtt);
+  void AdjustNetworkParameters(QuicBandwidth bandwidth,
+                               QuicTime::Delta rtt,
+                               bool allow_cwnd_to_decrease);
 
   // Retransmits the oldest pending packet there is still a tail loss probe
   // pending.  Invoked after OnRetransmissionTimeout.