Makes a QUIC method non-const.

net/quic/core/congestion_control/pacing_sender.h

Index: net/quic/core/congestion_control/pacing_sender.h
diff --git a/net/quic/core/congestion_control/pacing_sender.h b/net/quic/core/congestion_control/pacing_sender.h
index b297b8f80501f02eed318b1f415ad36770796ebd..65047210b911d678ecdbc1371cd2f90fcf5d7b6d 100644
--- a/net/quic/core/congestion_control/pacing_sender.h
+++ b/net/quic/core/congestion_control/pacing_sender.h
@@ -45,13 +45,15 @@ class QUIC_EXPORT_PRIVATE PacingSender {
       QuicTime event_time,
       const SendAlgorithmInterface::CongestionVector& acked_packets,
       const SendAlgorithmInterface::CongestionVector& lost_packets);
+
   bool OnPacketSent(QuicTime sent_time,
                     QuicByteCount bytes_in_flight,
                     QuicPacketNumber packet_number,
                     QuicByteCount bytes,
                     HasRetransmittableData is_retransmittable);
-  QuicTime::Delta TimeUntilSend(QuicTime now,
-                                QuicByteCount bytes_in_flight) const;
+
+  QuicTime::Delta TimeUntilSend(QuicTime now, QuicByteCount bytes_in_flight);
+
   QuicBandwidth PacingRate(QuicByteCount bytes_in_flight) const;
 
  private:
@@ -65,7 +67,7 @@ class QUIC_EXPORT_PRIVATE PacingSender {
   // Send time of the last packet considered delayed.
   QuicTime last_delayed_packet_sent_time_;
   QuicTime ideal_next_packet_send_time_;  // When can the next packet be sent.
-  mutable bool was_last_send_delayed_;  // True when the last send was delayed.
+  bool was_last_send_delayed_;  // True when the last send was delayed.
 
   DISALLOW_COPY_AND_ASSIGN(PacingSender);
 };