NQE: Store the current network quality in a single variable

net/nqe/network_quality_estimator.h

Index: net/nqe/network_quality_estimator.h
diff --git a/net/nqe/network_quality_estimator.h b/net/nqe/network_quality_estimator.h
index cb2ec31e6fed82cea8d8d760ebb06705a3a17d20..ac1e36f8373874676d12fb2291aa6cedf9743201 100644
--- a/net/nqe/network_quality_estimator.h
+++ b/net/nqe/network_quality_estimator.h
@@ -691,11 +691,8 @@ class NET_EXPORT NetworkQualityEstimator
   size_t rtt_observations_size_at_last_ect_computation_;
   size_t throughput_observations_size_at_last_ect_computation_;
 
-  // Current estimates of the HTTP RTT, transport RTT and downstream throughput
-  // (in kilobits per second).
-  base::TimeDelta http_rtt_;
-  base::TimeDelta transport_rtt_;
-  int32_t downstream_throughput_kbps_;
+  // Current estimates of the network quality.
+  nqe::internal::NetworkQuality network_quality_;
 
   // Current effective connection type. It is updated on connection change
   // events. It is also updated every time there is network traffic (provided