NQE: Allow algorithm to be set using variation params

net/nqe/network_quality_estimator.h

 // 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.
 
 #ifndef NET_NQE_NETWORK_QUALITY_ESTIMATOR_H_
 #define NET_NQE_NETWORK_QUALITY_ESTIMATOR_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 299 matching lines @@
   const char* GetNameForEffectiveConnectionType(
       EffectiveConnectionType type) const;
 
   // Overrides the tick clock used by |this| for testing.
   void SetTickClockForTesting(std::unique_ptr<base::TickClock> tick_clock);
 
  private:
   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);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest,
                            TestLRUCacheMaximumSize);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, TestGetMetricsSince);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest,
                            TestExternalEstimateProviderMergeEstimates);
 
   class SocketWatcher;
@@ skipping 102 matching lines @@
   // Returns true only if the |request| can be used for RTT estimation.
   bool RequestProvidesRTTObservation(const URLRequest& request) const;
 
   // Recomputes effective connection type, if it was computed more than the
   // specified duration ago, or if there has been a connection change recently.
   void MaybeRecomputeEffectiveConnectionType();
 
   // 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.
   enum NQEExternalEstimateProviderStatus {
     EXTERNAL_ESTIMATE_PROVIDER_STATUS_NOT_AVAILABLE,
     EXTERNAL_ESTIMATE_PROVIDER_STATUS_AVAILABLE,
     EXTERNAL_ESTIMATE_PROVIDER_STATUS_QUERIED,
     EXTERNAL_ESTIMATE_PROVIDER_STATUS_QUERY_SUCCESSFUL,
     EXTERNAL_ESTIMATE_PROVIDER_STATUS_CALLBACK,
     EXTERNAL_ESTIMATE_PROVIDER_STATUS_RTT_AVAILABLE,
@@ skipping 10 matching lines @@
   const bool use_localhost_requests_;
 
   // Determines if the responses smaller than |kMinTransferSizeInBytes|
   // or shorter than |kMinTransferSizeInBytes| can be used in estimating the
   // network quality. Set to true only for tests.
   const bool use_small_responses_;
 
   // 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_;
 
   // Minimum duration between two consecutive computations of effective
   // connection type. Set to non-zero value as a performance optimization.
   const base::TimeDelta effective_connection_type_recomputation_interval_;
 
   // Time when the effective connection type was last computed.
   base::TimeTicks last_effective_connection_type_computation_;
 
@@ skipping 66 matching lines @@
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<NetworkQualityEstimator> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkQualityEstimator);
 };
 
 }  // namespace net
 
 #endif  // NET_NQE_NETWORK_QUALITY_ESTIMATOR_H_