Add a network quality cache observer

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 268 matching lines @@
   // prediction should be recorded. Virtualized for testing.
   virtual const std::vector<base::TimeDelta>& GetAccuracyRecordingIntervals()
       const;
 
   // Overrides the tick clock used by |this| for testing.
   void SetTickClockForTesting(std::unique_ptr<base::TickClock> tick_clock);
 
   // Returns a random double in the range [0.0, 1.0). Virtualized for testing.
   virtual double RandDouble() const;
 
+  // Returns a pointer to |network_quality_store_|. Used only for testing.
+  nqe::internal::NetworkQualityStore* NetworkQualityStoreForTesting() const;
+
  private:
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest,
                            AdaptiveRecomputationEffectiveConnectionType);
   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);
@@ skipping 305 matching lines @@
   int32_t max_signal_strength_since_connection_change_;
 
   // It is costlier to add values to a sparse histogram. So, the correlation UMA
   // is recorded with |correlation_uma_logging_probability_| since recording it
   // in a sparse histogram for each request is unnecessary and cost-prohibitive.
   // e.g., if it is 0.0, then the UMA will never be recorded. On the other hand,
   // if it is 1.0, then it will be recorded for all valid HTTP requests.
   const double correlation_uma_logging_probability_;
 
   // Stores the qualities of different networks.
-  nqe::internal::NetworkQualityStore network_quality_store_;
+  std::unique_ptr<nqe::internal::NetworkQualityStore> network_quality_store_;
 
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<NetworkQualityEstimator> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkQualityEstimator);
 };
 
 }  // namespace net
 
 #endif  // NET_NQE_NETWORK_QUALITY_ESTIMATOR_H_