Add a ScopedFeatureList class for testing and start using it.

components/variations/variations_associated_data_unittest.cc

 // Copyright 2013 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.
 
 #include "components/variations/variations_associated_data.h"
 
 #include "base/feature_list.h"
 #include "base/macros.h"
 #include "base/metrics/field_trial.h"
+#include "base/test/scoped_feature_list.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace variations {
 
 namespace {
 
 const VariationID TEST_VALUE_A = 3300200;
 const VariationID TEST_VALUE_B = 3300201;
 
 // Convenience helper to retrieve the variations::VariationID for a FieldTrial.
 // Note that this will do the group assignment in |trial| if not already done.
 VariationID GetIDForTrial(IDCollectionKey key, base::FieldTrial* trial) {
   return GetGoogleVariationID(key, trial->trial_name(), trial->group_name());
 }
 
 // Call FieldTrialList::FactoryGetFieldTrial() with a future expiry date.
 scoped_refptr<base::FieldTrial> CreateFieldTrial(
     const std::string& trial_name,
     int total_probability,
     const std::string& default_group_name,
     int* default_group_number) {
   return base::FieldTrialList::FactoryGetFieldTrial(
       trial_name, total_probability, default_group_name,
       base::FieldTrialList::kNoExpirationYear, 1, 1,
       base::FieldTrial::SESSION_RANDOMIZED, default_group_number);
 }
 
-void CreateFeatureWithTrial(const base::Feature& feature,
-                            base::FeatureList::OverrideState override_state,
-                            base::FieldTrial* trial) {
-  base::FeatureList::ClearInstanceForTesting();
-  std::unique_ptr<base::FeatureList> feature_list(new base::FeatureList);
-  feature_list->RegisterFieldTrialOverride(feature.name, override_state,
-                                           trial);
-  base::FeatureList::SetInstance(std::move(feature_list));
-}
-
 }  // namespace
 
 class VariationsAssociatedDataTest : public ::testing::Test {
  public:
   VariationsAssociatedDataTest() : field_trial_list_(NULL) {
   }
 
   ~VariationsAssociatedDataTest() override {
     // Ensure that the maps are cleared between tests, since they are stored as
     // process singletons.
     testing::ClearAllVariationIDs();
     testing::ClearAllVariationParams();
   }
 
+  void CreateFeatureWithTrial(const base::Feature& feature,
+                              base::FeatureList::OverrideState override_state,
+                              base::FieldTrial* trial) {
+    std::unique_ptr<base::FeatureList> feature_list(new base::FeatureList);
+    feature_list->RegisterFieldTrialOverride(feature.name, override_state,
+                                             trial);
+    scoped_feature_list_.InitWithFeatureList(std::move(feature_list));
+  }
+
  private:
   base::FieldTrialList field_trial_list_;
+  base::test::ScopedFeatureList scoped_feature_list_;
 
   DISALLOW_COPY_AND_ASSIGN(VariationsAssociatedDataTest);
 };
 
 // Test that if the trial is immediately disabled, GetGoogleVariationID just
 // returns the empty ID.
 TEST_F(VariationsAssociatedDataTest, DisableImmediately) {
   int default_group_number = -1;
   scoped_refptr<base::FieldTrial> trial(
       CreateFieldTrial("trial", 100, "default", &default_group_number));
@@ skipping 351 matching lines @@
       CreateFieldTrial(kTrialName, 100, "A", NULL));
 
   CreateFeatureWithTrial(kFeature, base::FeatureList::OVERRIDE_DISABLE_FEATURE,
                          trial.get());
 
   std::map<std::string, std::string> actualParams;
   EXPECT_EQ(std::string(), GetVariationParamValueByFeature(kFeature, "x"));
 }
 
 }  // namespace variations