Create an interface for explicit notification of Dispatcher about

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 9a712017bd7590effde7c1a95fa063a0632816e5..2231157bbcc4f94e0e98770cbaf08802d408ff9d 100644
--- a/net/quic/quic_connection.h
+++ b/net/quic/quic_connection.h
@@ -75,8 +75,10 @@ class NET_EXPORT_PRIVATE QuicConnectionVisitorInterface {
 
   // Called when the connection is closed either locally by the framer, or
   // remotely by the peer.
-  virtual void OnConnectionClosed(QuicErrorCode error,
-                                  bool from_peer) = 0;
+  virtual void OnConnectionClosed(QuicErrorCode error, bool from_peer) = 0;
+
+  // Called when the connection failed to write because the socket was blocked.
+  virtual void OnWriteBlocked() = 0;
 
   // Called once a specific QUIC version is agreed by both endpoints.
   virtual void OnSuccessfulVersionNegotiation(const QuicVersion& version) = 0;