Change the QUIC CongestionMap to be based on a vector.

net/quic/congestion_control/send_algorithm_interface.h

Index: net/quic/congestion_control/send_algorithm_interface.h
diff --git a/net/quic/congestion_control/send_algorithm_interface.h b/net/quic/congestion_control/send_algorithm_interface.h
index 5d1f6df3532f3398ff6ab08ee07f33b1315926e8..24d965d0d54fc3f315f977b9e4723077b693cec7 100644
--- a/net/quic/congestion_control/send_algorithm_interface.h
+++ b/net/quic/congestion_control/send_algorithm_interface.h
@@ -25,7 +25,9 @@ class RttStats;
 
 class NET_EXPORT_PRIVATE SendAlgorithmInterface {
  public:
-  typedef std::map<QuicPacketSequenceNumber, TransmissionInfo> CongestionMap;
+  // A sorted vector of packets.
+  typedef std::vector<std::pair<QuicPacketSequenceNumber, TransmissionInfo>>
+      CongestionVector;
 
   static SendAlgorithmInterface* Create(const QuicClock* clock,
                                         const RttStats* rtt_stats,
@@ -48,8 +50,8 @@ class NET_EXPORT_PRIVATE SendAlgorithmInterface {
   // any packets considered acked or lost as a result of the congestion event.
   virtual void OnCongestionEvent(bool rtt_updated,
                                  QuicByteCount bytes_in_flight,
-                                 const CongestionMap& acked_packets,
-                                 const CongestionMap& lost_packets) = 0;
+                                 const CongestionVector& acked_packets,
+                                 const CongestionVector& lost_packets) = 0;
 
   // Inform that we sent |bytes| to the wire, and if the packet is
   // retransmittable. Returns true if the packet should be tracked by the