Add a ScopedFeatureList class for testing and start using it.

components/autofill/core/browser/autofill_merge_unittest.cc

Index: components/autofill/core/browser/autofill_merge_unittest.cc
diff --git a/components/autofill/core/browser/autofill_merge_unittest.cc b/components/autofill/core/browser/autofill_merge_unittest.cc
index 3baf43244ecf6421c1bfb7802da92a1eb8766586..dfa93142527c1beb8c0671749aad8b99e208bc94 100644
--- a/components/autofill/core/browser/autofill_merge_unittest.cc
+++ b/components/autofill/core/browser/autofill_merge_unittest.cc
@@ -16,6 +16,7 @@
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/test/scoped_feature_list.h"
 #include "components/autofill/core/browser/autofill_experiments.h"
 #include "components/autofill/core/browser/autofill_test_utils.h"
 #include "components/autofill/core/browser/autofill_type.h"
@@ -183,6 +184,7 @@ class AutofillMergeTest : public DataDrivenTest,
   PersonalDataManagerMock personal_data_;
 
  private:
+  base::test::ScopedFeatureList scoped_feature_list_;
   std::map<std::string, ServerFieldType> string_to_field_type_map_;
 
   DISALLOW_COPY_AND_ASSIGN(AutofillMergeTest);
@@ -201,12 +203,7 @@ AutofillMergeTest::~AutofillMergeTest() {
 
 void AutofillMergeTest::SetUp() {
   test::DisableSystemServices(nullptr);
-
-  base::FeatureList::ClearInstanceForTesting();
-  std::unique_ptr<base::FeatureList> feature_list(new base::FeatureList);
-  feature_list->InitializeFromCommandLine(kAutofillProfileCleanup.name,
-                                          std::string());
-  base::FeatureList::SetInstance(std::move(feature_list));
+  scoped_feature_list_.InitAndEnableFeature(kAutofillProfileCleanup);
 }
 
 void AutofillMergeTest::TearDown() {