QUIC varz to track measured and predicted bandwidth and rtt histograms

net/quic/congestion_control/tcp_cubic_sender.cc

Index: net/quic/congestion_control/tcp_cubic_sender.cc
diff --git a/net/quic/congestion_control/tcp_cubic_sender.cc b/net/quic/congestion_control/tcp_cubic_sender.cc
index a9ca66c0cfb124e79916b50f93dd1bada6e64c7f..95fa6cccc3be38795477a0e957dcb612c5f97b41 100644
--- a/net/quic/congestion_control/tcp_cubic_sender.cc
+++ b/net/quic/congestion_control/tcp_cubic_sender.cc
@@ -196,6 +196,10 @@ QuicBandwidth TcpCubicSender::BandwidthEstimate() const {
                                               rtt_stats_->SmoothedRtt());
 }
 
+bool TcpCubicSender::HasReliableBandwidthEstimate() const {
+  return !InSlowStart() && !InRecovery();
+}
+
 QuicTime::Delta TcpCubicSender::RetransmissionDelay() const {
   if (!rtt_stats_->HasUpdates()) {
     return QuicTime::Delta::Zero();