Expose transport RTT estimate from Network Quality Estimator (NQE)

net/nqe/network_quality_estimator.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/nqe/network_quality_estimator.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 #include <utility>
@@ skipping 1749 matching lines @@
     nqe::internal::CachedNetworkQuality cached_network_quality(
         base::TimeTicks::Now(),
         params_.TypicalNetworkQuality(effective_connection_type),
         effective_connection_type);
 
     network_quality_store_->Add(it.first, cached_network_quality);
     MaybeUpdateNetworkQualityFromCache(it.first, cached_network_quality);
   }
 }
 
+base::Optional<base::TimeDelta> NetworkQualityEstimator::GetTransportRTT()
+    const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (network_quality_.transport_rtt() == nqe::internal::InvalidRTT())
+    return base::Optional<base::TimeDelta>();
+  return network_quality_.transport_rtt();
+}
+
 void NetworkQualityEstimator::MaybeUpdateNetworkQualityFromCache(
     const nqe::internal::NetworkID& network_id,
     const nqe::internal::CachedNetworkQuality& cached_network_quality) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   if (!params_.persistent_cache_reading_enabled())
     return;
   if (network_id != current_network_id_)
     return;
 
@@ skipping 53 matching lines @@
   return base::Optional<base::TimeDelta>();
 }
 
 base::Optional<int32_t>
 NetworkQualityEstimator::NetworkQualityProvider::GetDownstreamThroughputKbps()
     const {
   return base::Optional<int32_t>();
 }
 
 }  // namespace net