Discard all useless QUIC retransmissions instead of only the most recent

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 6332706326e166d9ee4096806612fd90cf26c931..2580654b82b64fa6ce16012925d1add33580c384 100644
--- a/net/quic/quic_unacked_packet_map.cc
+++ b/net/quic/quic_unacked_packet_map.cc
@@ -60,7 +60,6 @@ void QuicUnackedPacketMap::RemoveObsoletePackets() {
     if (!IsPacketRemovable(least_unacked_, unacked_packets_.front())) {
       break;
     }
-    delete unacked_packets_.front().all_transmissions;
     unacked_packets_.pop_front();
     ++least_unacked_;
   }
@@ -91,18 +90,21 @@ void QuicUnackedPacketMap::OnRetransmittedPacket(
   transmission_info->retransmittable_frames = NULL;
   // Only keep one transmission older than largest observed, because only the
   // most recent is expected to possibly be a spurious retransmission.
-  if (transmission_info->all_transmissions != NULL &&
-      *(++transmission_info->all_transmissions->begin()) < largest_observed_) {
+  while (transmission_info->all_transmissions != NULL &&
+         transmission_info->all_transmissions->size() > 1 &&
+         *(++transmission_info->all_transmissions->begin())
+             < largest_observed_) {
     QuicPacketSequenceNumber old_transmission =
         *transmission_info->all_transmissions->begin();
     TransmissionInfo* old_info =
         &unacked_packets_[old_transmission - least_unacked_];
     // Don't remove old packets if they're still in flight.
-    if (!old_info->in_flight) {
-      old_info->all_transmissions->pop_front();
-      // This will cause the packet be removed in RemoveObsoletePackets.
-      old_info->all_transmissions = NULL;
+    if (old_info->in_flight) {
+      break;
     }
+    old_info->all_transmissions->pop_front();
+    // This will cause the packet be removed in RemoveObsoletePackets.
+    old_info->all_transmissions = NULL;
   }
   // Don't link old transmissions to new ones when version or
   // encryption changes.