Use byte conservation instead of packet conservation in QUIC's Slow Start Large Recovery experiment…

net/quic/quic_connection_stats.h

Index: net/quic/quic_connection_stats.h
diff --git a/net/quic/quic_connection_stats.h b/net/quic/quic_connection_stats.h
index b955b661b02eff2eb41761de51d7c934086c9c19..2f491ae832ae7fb2fbc83c7419f61992fb312732 100644
--- a/net/quic/quic_connection_stats.h
+++ b/net/quic/quic_connection_stats.h
@@ -54,6 +54,8 @@ struct NET_EXPORT_PRIVATE QuicConnectionStats {
   QuicPacketCount slowstart_packets_sent;
   // Number of packets lost exiting slow start.
   QuicPacketCount slowstart_packets_lost;
+  // Number of bytes lost exiting slow start.
+  QuicByteCount slowstart_bytes_lost;
 
   QuicPacketCount packets_dropped;  // Duplicate or less than least unacked.
   size_t crypto_retransmit_count;