Add an IncreaseLargestObserved to QuicUnackedPacketMap to remove the rtt

net/quic/quic_unacked_packet_map.cc

Index: net/quic/quic_unacked_packet_map.cc
diff --git a/net/quic/quic_unacked_packet_map.cc b/net/quic/quic_unacked_packet_map.cc
index 053b445b0e9c2fce2abb4055600df5db3dfcb490..c84ab1109e9b7b9272b917263f6e8c9a46d86713 100644
--- a/net/quic/quic_unacked_packet_map.cc
+++ b/net/quic/quic_unacked_packet_map.cc
@@ -15,6 +15,7 @@ namespace net {
 
 QuicUnackedPacketMap::QuicUnackedPacketMap()
     : largest_sent_packet_(0),
+      largest_observed_(0),
       bytes_in_flight_(0),
       pending_crypto_packet_count_(0) {
 }
@@ -123,16 +124,15 @@ void QuicUnackedPacketMap::NackPacket(QuicPacketSequenceNumber sequence_number,
 }
 
 void QuicUnackedPacketMap::RemoveRetransmittability(
-    QuicPacketSequenceNumber sequence_number,
-    QuicPacketSequenceNumber largest_observed) {
+    QuicPacketSequenceNumber sequence_number) {
   UnackedPacketMap::iterator it = unacked_packets_.find(sequence_number);
   if (it == unacked_packets_.end()) {
-    LOG(DFATAL) << "packet is not unacked: " << sequence_number;
+    DVLOG(1) << "packet is not in unacked_packets: " << sequence_number;
     return;
   }
   SequenceNumberSet* all_transmissions = it->second.all_transmissions;
   // TODO(ianswett): Consider optimizing this for lone packets.
-  // TODO(ianswett): Consider adding a check to ensure there are retranmittable
+  // TODO(ianswett): Consider adding a check to ensure there are retransmittable
   // frames associated with this packet.
   for (SequenceNumberSet::reverse_iterator it = all_transmissions->rbegin();
        it != all_transmissions->rend(); ++it) {
@@ -143,7 +143,7 @@ void QuicUnackedPacketMap::RemoveRetransmittability(
       continue;
     }
     MaybeRemoveRetransmittableFrames(transmission_info);
-    if (sequence_number <= largest_observed && !transmission_info->pending) {
+    if (*it <= largest_observed_ && !transmission_info->pending) {
       unacked_packets_.erase(*it);
     } else {
       transmission_info->all_transmissions = new SequenceNumberSet();
@@ -166,27 +166,29 @@ void QuicUnackedPacketMap::MaybeRemoveRetransmittableFrames(
   }
 }
 
-void QuicUnackedPacketMap::RemoveRttOnlyPacket(
-    QuicPacketSequenceNumber sequence_number) {
-  UnackedPacketMap::iterator it = unacked_packets_.find(sequence_number);
-  if (it == unacked_packets_.end()) {
-    LOG(DFATAL) << "packet is not unacked: " << sequence_number;
-    return;
+void QuicUnackedPacketMap::IncreaseLargestObserved(
+    QuicPacketSequenceNumber largest_observed) {
+  DCHECK_LT(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;
+    unacked_packets_.erase(sequence_number);
   }
-  TransmissionInfo* transmission_info = &it->second;
-  DCHECK(!transmission_info->pending);
-  DCHECK(transmission_info->retransmittable_frames == NULL);
-  DCHECK_EQ(1u, transmission_info->all_transmissions->size());
-  delete transmission_info->all_transmissions;
-  unacked_packets_.erase(it);
 }
 
-// static
-bool QuicUnackedPacketMap::IsForRttOnly(
-    const TransmissionInfo& transmission_info) {
-  return !transmission_info.pending &&
-      transmission_info.retransmittable_frames == NULL &&
-      transmission_info.all_transmissions->size() == 1;
+bool QuicUnackedPacketMap::IsPacketUseless(
+    UnackedPacketMap::const_iterator it) {
+  return it->first <= largest_observed_ &&
+      !it->second.pending &&
+      it->second.retransmittable_frames == NULL &&
+      it->second.all_transmissions->size() == 1;
 }
 
 bool QuicUnackedPacketMap::IsUnacked(
@@ -207,6 +209,10 @@ void QuicUnackedPacketMap::SetNotPending(
     bytes_in_flight_ -= it->second.bytes_sent;
     it->second.pending = false;
   }
+  if (IsPacketUseless(it)) {
+    delete it->second.all_transmissions;
+    unacked_packets_.erase(it);
+  }
 }
 
 bool QuicUnackedPacketMap::HasUnackedPackets() const {