Remove largest_observed_ from QuicSentPacketManager, since it's also in

net/quic/quic_unacked_packet_map.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/quic_unacked_packet_map.h"
 
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "net/quic/quic_connection_stats.h"
 #include "net/quic/quic_utils_chromium.h"
@@ skipping 166 matching lines @@
             == IS_HANDSHAKE) {
       --pending_crypto_packet_count_;
     }
     delete transmission_info->retransmittable_frames;
     transmission_info->retransmittable_frames = NULL;
   }
 }
 
 void QuicUnackedPacketMap::IncreaseLargestObserved(
     QuicPacketSequenceNumber largest_observed) {
-  DCHECK_LT(largest_observed_, largest_observed);
+  DCHECK_LE(largest_observed_, largest_observed);
   largest_observed_ = largest_observed;
   UnackedPacketMap::iterator it = unacked_packets_.begin();
   while (it != unacked_packets_.end() && it->first <= largest_observed_) {
     if (!IsPacketUseless(it)) {
       ++it;
       continue;
     }
     delete it->second.all_transmissions;
     QuicPacketSequenceNumber sequence_number = it->first;
     ++it;
@@ skipping 147 matching lines @@
   }
   DCHECK(!it->second.in_flight);
   DCHECK_NE(0u, it->second.bytes_sent);
   DCHECK(it->second.sent_time.IsInitialized());
 
   bytes_in_flight_ += it->second.bytes_sent;
   it->second.in_flight = true;
 }
 
 }  // namespace net