Add a ScopedFeatureList class for testing and start using it.

components/translate/core/browser/translate_ui_delegate_unittest.cc

 // 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.
 
 #include "components/translate/core/browser/translate_ui_delegate.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/stringprintf.h"
+#include "base/test/scoped_feature_list.h"
 #include "build/build_config.h"
 #include "components/infobars/core/infobar.h"
 #include "components/pref_registry/pref_registry_syncable.h"
 #include "components/pref_registry/testing_pref_service_syncable.h"
 #include "components/translate/core/browser/mock_translate_driver.h"
 #include "components/translate/core/browser/translate_client.h"
 #include "components/translate/core/browser/translate_infobar_delegate.h"
 #include "components/translate/core/browser/translate_manager.h"
 #include "components/translate/core/browser/translate_prefs.h"
 #include "components/variations/variations_associated_data.h"
@@ skipping 64 matching lines @@
 
     client_.reset(new MockTranslateClient(&driver_, pref_service_.get()));
 
     manager_.reset(new TranslateManager(client_.get(), "hi"));
     manager_->GetLanguageState().set_translation_declined(false);
 
     delegate_.reset(
         new TranslateUIDelegate(manager_->GetWeakPtr(), "ar", "fr"));
 
     ASSERT_FALSE(client_->GetTranslatePrefs()->IsTooOftenDenied("ar"));
-    base::FeatureList::ClearInstanceForTesting();
-    base::FeatureList::SetInstance(base::WrapUnique(new base::FeatureList));
   }
 
   void TurnOnTranslate2016Q2UIFlag() {
-    base::FeatureList::ClearInstanceForTesting();
-    std::unique_ptr<base::FeatureList> feature_list(new base::FeatureList);
-    feature_list->InitializeFromCommandLine(translate::kTranslateUI2016Q2.name,
-                                            std::string());
-    base::FeatureList::SetInstance(std::move(feature_list));
+    scoped_feature_list_.InitAndEnableFeature(translate::kTranslateUI2016Q2);
   }
 
   MockTranslateDriver driver_;
   std::unique_ptr<MockTranslateClient> client_;
   std::unique_ptr<user_prefs::TestingPrefServiceSyncable> pref_service_;
   std::unique_ptr<TranslateManager> manager_;
   std::unique_ptr<TranslateUIDelegate> delegate_;
+  base::test::ScopedFeatureList scoped_feature_list_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TranslateUIDelegateTest);
 };
 
 TEST_F(TranslateUIDelegateTest, CheckDeclinedFalse) {
   std::unique_ptr<TranslatePrefs> prefs(client_->GetTranslatePrefs());
   for (int i = 0; i < 10; i++) {
     prefs->IncrementTranslationAcceptedCount("ar");
   }
@@ skipping 83 matching lines @@
   prefs->IncrementTranslationAcceptedCount("ar");
 
   EXPECT_FALSE(delegate_->ShouldAlwaysTranslateBeCheckedByDefault());
 }
 
 // TODO(ftang) Currently this file only test TranslationDeclined(), we
 // need to add the test for other functions soon to increase the test
 // coverage.
 
 }  // namespace translate