QUIC varz to track measured and predicted bandwidth and rtt histograms

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 01bc2334b6060c3f712b6387725d3934b9a9ad38..98437ff9ceb8fdebc1a0316961f4fa12cd9ebf2c 100644
--- a/net/quic/congestion_control/send_algorithm_interface.h
+++ b/net/quic/congestion_control/send_algorithm_interface.h
@@ -80,6 +80,9 @@ class NET_EXPORT_PRIVATE SendAlgorithmInterface {
   // Returns 0 when it does not have an estimate.
   virtual QuicBandwidth BandwidthEstimate() const = 0;
 
+  // Returns true if the current bandwidth estimate is reliable.
+  virtual bool HasReliableBandwidthEstimate() const = 0;
+
   // Get the send algorithm specific retransmission delay, called RTO in TCP,
   // Note 1: the caller is responsible for sanity checking this value.
   // Note 2: this will return zero if we don't have enough data for an estimate.