NQE: Change GetEffectiveConnectionType to return last ECT

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 130 matching lines @@
   // Allows the responses smaller than |kMinTransferSizeInBits| to be used for
   // network quality estimation.
   NetworkQualityEstimator(
       std::unique_ptr<ExternalEstimateProvider> external_estimates_provider,
       const std::map<std::string, std::string>& variation_params,
       bool use_local_host_requests_for_tests,
       bool use_smaller_responses_for_tests);
 
   ~NetworkQualityEstimator() override;
 
-  // Returns the effective type of the current connection. Virtualized for
-  // testing.
+  // Returns the last computed effective type of the current connection. The
+  // effective connection type is computed by the network quality estimator at
+  // regular intervals and at certain events (e.g., connection change).
+  // Virtualized for testing.
   virtual EffectiveConnectionType GetEffectiveConnectionType() const;
 
   // Returns the effective type of the current connection based on only the
   // samples observed after |start_time|. This should only be used for
   // recording the metrics. Virtualized for testing.
   virtual EffectiveConnectionType GetRecentEffectiveConnectionType(
       const base::TimeTicks& start_time) const;
 
   // Adds |observer| to the list of effective connection type observers. Must be
   // called on the IO thread.
@@ skipping 256 matching lines @@
 
   void NotifyObserversOfRTT(const RttObservation& observation);
 
   void NotifyObserversOfThroughput(const ThroughputObservation& observation);
 
   // 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();
+  void MaybeComputeEffectiveConnectionType();
 
   // Notify observers of a change in effective connection type.
   void NotifyObserversOfEffectiveConnectionTypeChanged();
 
   // Records NQE accuracy metrics. |measuring_duration| should belong to the
   // vector returned by AccuracyRecordingIntervals().
   // RecordAccuracyAfterMainFrame should be called |measuring_duration| after a
   // main frame request is observed.
   void RecordAccuracyAfterMainFrame(base::TimeDelta measuring_duration) const;
 
@@ skipping 36 matching lines @@
 
   // Records a correlation metric that can be used for computing the correlation
   // between HTTP-layer RTT, transport-layer RTT, throughput and the time
   // taken to complete |request|.
   void RecordCorrelationMetric(const URLRequest& request) const;
 
   // Returns true if transport RTT should be used for computing the effective
   // connection type.
   bool UseTransportRTT() const;
 
+  // Forces computation of effective connection type, and notifies observers
+  // if there is a change in its value.
+  void ComputeEffectiveConnectionType();
+
   // Determines if the requests to local host can be used in estimating the
   // network quality. Set to true only for tests.
   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.
   bool use_small_responses_;
 
   // The factor by which the weight of an observation reduces every second.
@@ skipping 126 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_