NQE: Add net log events when there is a significant change in metrics

net/nqe/network_quality_estimator_test_util.h

 // Copyright 2016 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_TEST_UTIL_H_
 #define NET_NQE_NETWORK_QUALITY_ESTIMATOR_TEST_UTIL_H_
 
 #include <map>
 #include <memory>
 #include <string>
@@ skipping 163 matching lines @@
   const std::vector<base::TimeDelta>& GetAccuracyRecordingIntervals()
       const override;
 
   void set_rand_double(double rand_double) { rand_double_ = rand_double; }
 
   double RandDouble() const override;
 
   // Returns the number of entries in |net_log_| that have type set to |type|.
   int GetEntriesCount(NetLogEventType type) const;
 
+  // Returns the value of the parameter with name |key| from the last net log
+  // entry that has type set to |type|. Different methods are provided for
+  // values of different types.
+  std::string GetNetLogLastStringValue(NetLogEventType type,
+                                       const std::string& key) const;
+  int GetNetLogLastIntegerValue(NetLogEventType type,
+                                const std::string& key) const;
+
   using NetworkQualityEstimator::SetTickClockForTesting;
   using NetworkQualityEstimator::OnConnectionTypeChanged;
 
  private:
   class LocalHttpTestServer : public EmbeddedTestServer {
    public:
     explicit LocalHttpTestServer(const base::FilePath& document_root);
   };
 
   // NetworkQualityEstimator implementation that returns the overridden
@@ skipping 37 matching lines @@
 
   // Net log provided to network quality estimator.
   std::unique_ptr<net::BoundTestNetLog> net_log_;
 
   DISALLOW_COPY_AND_ASSIGN(TestNetworkQualityEstimator);
 };
 
 }  // namespace net
 
 #endif  // NET_NQE_NETWORK_QUALITY_ESTIMATOR_TEST_UTIL_H_