Notify quicconnectionvisitorinterface when forward progress is made after path degrading.

No flag protection, no-op in the shared code. Chromium QuicChromiumClientSession will override OnForwardProgressMadeAfterPathDegrading to handle differently.

PiperOrigin-RevId: 315999536
Change-Id: Ibc7ac1ca4c8a38cba29b67f5bd366b29d9d85df3
diff --git a/quic/core/quic_connection.h b/quic/core/quic_connection.h
index 5683c8b..d43093c 100644
--- a/quic/core/quic_connection.h
+++ b/quic/core/quic_connection.h
@@ -146,6 +146,9 @@
   // Called when the peer seems unreachable over the current path.
   virtual void OnPathDegrading() = 0;
 
+  // Called when forward progress made after path degrading.
+  virtual void OnForwardProgressMadeAfterPathDegrading() = 0;
+
   // Called when the connection sends ack after
   // max_consecutive_num_packets_with_no_retransmittable_frames_ consecutive not
   // retransmittable packets sent. To instigate an ack from peer, a