API changes to Write path Session on down for FEC protection.

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 9e93715e7cd6734c7ed3b2288e9e785146920a27..acd8f02dede4468e5814dd3903491d3193ae5abb 100644
--- a/net/quic/quic_connection.h
+++ b/net/quic/quic_connection.h
@@ -230,7 +230,10 @@ class NET_EXPORT_PRIVATE QuicConnection
   // Returns a pair with the number of bytes consumed from data, and a boolean
   // indicating if the fin bit was consumed.  This does not indicate the data
   // has been sent on the wire: it may have been turned into a packet and queued
-  // if the socket was unexpectedly blocked.
+  // if the socket was unexpectedly blocked. |fec_protection| indicates if
+  // data is to be FEC protected. Note that data that is sent immediately
+  // following MUST_FEC_PROTECT data may get protected by falling within the
+  // same FEC group.
   // If |delegate| is provided, then it will be informed once ACKs have been
   // received for all the packets written in this call.
   // The |delegate| is not owned by the QuicConnection and must outlive it.
@@ -238,6 +241,7 @@ class NET_EXPORT_PRIVATE QuicConnection
                                   const IOVector& data,
                                   QuicStreamOffset offset,
                                   bool fin,
+                                  FecProtection fec_protection,
                                   QuicAckNotifier::DelegateInterface* delegate);
 
   // Send a RST_STREAM frame to the peer.