Revert of Landing Recent QUIC Changes.

net/quic/congestion_control/tcp_loss_algorithm.cc

Index: net/quic/congestion_control/tcp_loss_algorithm.cc
diff --git a/net/quic/congestion_control/tcp_loss_algorithm.cc b/net/quic/congestion_control/tcp_loss_algorithm.cc
index 557681ee1864932a3da015054e208e03a97a259f..8dad3f18429279d8401424d3c727657b9767401a 100644
--- a/net/quic/congestion_control/tcp_loss_algorithm.cc
+++ b/net/quic/congestion_control/tcp_loss_algorithm.cc
@@ -37,34 +37,33 @@
   loss_detection_timeout_ = QuicTime::Zero();
   QuicTime::Delta loss_delay =
       rtt_stats.SmoothedRtt().Multiply(kEarlyRetransmitLossDelayMultiplier);
-  QuicPacketSequenceNumber sequence_number = unacked_packets.GetLeastUnacked();
+
   for (QuicUnackedPacketMap::const_iterator it = unacked_packets.begin();
-       it != unacked_packets.end() && sequence_number <= largest_observed;
-       ++it, ++sequence_number) {
-    if (!it->in_flight) {
+       it != unacked_packets.end() && it->first <= largest_observed; ++it) {
+    if (!it->second.in_flight) {
       continue;
     }
 
-    LOG_IF(DFATAL, it->nack_count == 0)
+    LOG_IF(DFATAL, it->second.nack_count == 0)
         << "All packets less than largest observed should have been nacked.";
-    if (it->nack_count >= kNumberOfNacksBeforeRetransmission) {
-      lost_packets.insert(sequence_number);
+    if (it->second.nack_count >= kNumberOfNacksBeforeRetransmission) {
+      lost_packets.insert(it->first);
       continue;
     }
 
     // Only early retransmit(RFC5827) when the last packet gets acked and
     // there are retransmittable packets in flight.
     // This also implements a timer-protected variant of FACK.
-    if (it->retransmittable_frames &&
+    if (it->second.retransmittable_frames &&
         unacked_packets.largest_sent_packet() == largest_observed) {
       // Early retransmit marks the packet as lost once 1.25RTTs have passed
       // since the packet was sent and otherwise sets an alarm.
-      if (time >= it->sent_time.Add(loss_delay)) {
-        lost_packets.insert(sequence_number);
+      if (time >= it->second.sent_time.Add(loss_delay)) {
+        lost_packets.insert(it->first);
       } else {
         // Set the timeout for the earliest retransmittable packet where early
         // retransmit applies.
-        loss_detection_timeout_ = it->sent_time.Add(loss_delay);
+        loss_detection_timeout_ = it->second.sent_time.Add(loss_delay);
         break;
       }
     }