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..cdc83c7911b171e7b9b8c69c4303bbd3e7646007 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 algorithm 0 to compute the
+  // effective connection type. This algorithm uses HTTP RTT and downlink
+  // throughput as inputs, and requires both inputs to have a valid value.
+  // This method should be called only if |algorithm_| is 0.
+  EffectiveConnectionType GetRecentEffectiveConnectionTypeAlgorithm0(
+      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 +479,11 @@ 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 default value of 0.
+  const int32_t algorithm_;

[bengr, 2016/06/02 22:59:43]

Letters are more intuitive than numbers for experiments, at least to me,
probably because of the existence of A/B testing.

[tbansal1, 2016/06/03 00:50:10]

Done.

+
   // Tick clock used by the network quality estimator.
   std::unique_ptr<base::TickClock> tick_clock_;