Mark ECT as ambiguous if there is a change in the connection type.

components/metrics/net/network_metrics_provider.h

 // Copyright 2014 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 COMPONENTS_METRICS_NET_NETWORK_METRICS_PROVIDER_H_
 #define COMPONENTS_METRICS_NET_NETWORK_METRICS_PROVIDER_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 46 matching lines @@
   // should be set if it is useful to attach the quality of the network to the
   // metrics report.
   NetworkMetricsProvider(std::unique_ptr<NetworkQualityEstimatorProvider>
                              network_quality_estimator_provider,
                          base::TaskRunner* io_task_runner);
 
   ~NetworkMetricsProvider() override;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(NetworkMetricsProviderTest, EffectiveConnectionType);
+  FRIEND_TEST_ALL_PREFIXES(NetworkMetricsProviderTest,
+                           ECTAmbiguousOnConnectionTypeChange);
 
   // Listens to the changes in the effective conection type.
   class EffectiveConnectionTypeObserver;
 
   // MetricsProvider:
   void ProvideGeneralMetrics(ChromeUserMetricsExtension* uma_proto) override;
   void ProvideSystemProfileMetrics(SystemProfileProto* system_profile) override;
 
   // ConnectionTypeObserver:
   void OnConnectionTypeChanged(
@@ skipping 69 matching lines @@
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<NetworkMetricsProvider> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkMetricsProvider);
 };
 
 }  // namespace metrics
 
 #endif  // COMPONENTS_METRICS_NET_NETWORK_METRICS_PROVIDER_H_