Add a ScopedFeatureList class for testing and start using it.

components/translate/core/browser/translate_prefs_unittest.cc

Index: components/translate/core/browser/translate_prefs_unittest.cc
diff --git a/components/translate/core/browser/translate_prefs_unittest.cc b/components/translate/core/browser/translate_prefs_unittest.cc
index 881718d92d8e193fe97b1931146b68d3ed47de57..5d77a3397837865caf14edb97db6fb4d5bbda76f 100644
--- a/components/translate/core/browser/translate_prefs_unittest.cc
+++ b/components/translate/core/browser/translate_prefs_unittest.cc
@@ -9,6 +9,7 @@
 #include <utility>
 #include <vector>
 
+#include "base/test/scoped_feature_list.h"
 #include "build/build_config.h"
 #include "components/pref_registry/testing_pref_service_syncable.h"
 #include "components/prefs/scoped_user_pref_update.h"
@@ -50,19 +51,11 @@ class TranslatePrefTest : public testing::Test {
     return update.GetOldestDenialTime();
   }
 
-  void SetUp() override {
-    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);
   }
 
+  base::test::ScopedFeatureList scoped_feature_list_;
   std::unique_ptr<user_prefs::TestingPrefServiceSyncable> prefs_;
   std::unique_ptr<translate::TranslatePrefs> translate_prefs_;