Remove largest_observed_ from QuicSentPacketManager, since it's also in

net/quic/quic_sent_packet_manager.h

Index: net/quic/quic_sent_packet_manager.h
diff --git a/net/quic/quic_sent_packet_manager.h b/net/quic/quic_sent_packet_manager.h
index 8b7bcbd58f236c7741de23f31282bfb56220d4bd..342dd3d4653144005b9ad3ae86db254a8ba58c10 100644
--- a/net/quic/quic_sent_packet_manager.h
+++ b/net/quic/quic_sent_packet_manager.h
@@ -223,7 +223,7 @@ class NET_EXPORT_PRIVATE QuicSentPacketManager {
   }
 
   QuicPacketSequenceNumber largest_observed() const {
-    return largest_observed_;
+    return unacked_packets_.largest_observed();
   }
 
   QuicPacketSequenceNumber least_packet_awaited_by_peer() {
@@ -358,10 +358,6 @@ class NET_EXPORT_PRIVATE QuicSentPacketManager {
   scoped_ptr<SendAlgorithmInterface> send_algorithm_;
   scoped_ptr<LossDetectionInterface> loss_algorithm_;
 
-  // The largest sequence number which we have sent and received an ACK for
-  // from the peer.
-  QuicPacketSequenceNumber largest_observed_;
-
   // Least sequence number which the peer is still waiting for.
   QuicPacketSequenceNumber least_packet_awaited_by_peer_;