NQE: Allow algorithm to be set using variation params

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 2abc9fd7d6f7bffbcea10f7262ff497dbeb225c8..667b573c593519e8bf349724538147a3aa582fe2 100644
--- a/net/nqe/network_quality_estimator.h
+++ b/net/nqe/network_quality_estimator.h
@@ -317,6 +317,8 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, StoreObservations);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, TestAddObservation);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, ObtainOperatingParams);
+  FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest,
+                           ObtainAlgorithmToUseFromParams);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, HalfLifeParam);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, ComputedPercentiles);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, TestCaching);
@@ -439,6 +441,14 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
   // Notify observers of a change in effective connection type.
   void NotifyObserversOfEffectiveConnectionTypeChanged();
 
+  // Returns the effective type of the current connection based on only the
+  // samples observed after |start_time|. Uses HTTP RTT and downstream
+  // throughput to compute the effective connection type, and requires both of
+  // them to have a valid value.
+  EffectiveConnectionType
+  GetRecentEffectiveConnectionTypeHttpRTTAndDownstreamThroughput(
+      const base::TimeTicks& start_time) const;
+
   // Values of external estimate provider status. This enum must remain
   // synchronized with the enum of the same name in
   // metrics/histograms/histograms.xml.
@@ -469,6 +479,12 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
   // The factor by which the weight of an observation reduces every second.
   const double weight_multiplier_per_second_;
 
+  // Algorithm to use for computing effective connection type. The value is
+  // obtained from field trial parameters. If the value from field trial
+  // parameters is unavailable, it is set to
+  // |kDefaultEffectiveConnectionTypeAlgorithm|.
+  const std::string algorithm_;
+
   // Tick clock used by the network quality estimator.
   std::unique_ptr<base::TickClock> tick_clock_;