Deprecate quic_respect_send_alarm2.

net/quic/congestion_control/tcp_cubic_sender_base.cc

Index: net/quic/congestion_control/tcp_cubic_sender_base.cc
diff --git a/net/quic/congestion_control/tcp_cubic_sender_base.cc b/net/quic/congestion_control/tcp_cubic_sender_base.cc
index deb5a4f35dea4dadc967e9e0af0881db0ada678e..51e9bed1492479166ef1b672e45f4dbbd3381dde 100644
--- a/net/quic/congestion_control/tcp_cubic_sender_base.cc
+++ b/net/quic/congestion_control/tcp_cubic_sender_base.cc
@@ -178,7 +178,7 @@ QuicTime::Delta TcpCubicSenderBase::TimeUntilSend(
     QuicByteCount bytes_in_flight,
     HasRetransmittableData has_retransmittable_data) const {
   if (has_retransmittable_data == NO_RETRANSMITTABLE_DATA) {
-    DCHECK(!FLAGS_quic_respect_send_alarm2);
+    QUIC_BUG << "TimeUntilSend's has_retransmittable_data argument deprecated.";
     // For TCP we can always send an ACK immediately.
     return QuicTime::Delta::Zero();
   }