[ObjC ARC] Converts ios/chrome/browser/ui/settings:unit_tests to ARC.

ios/chrome/browser/payments/payment_request_error_view_controller_unittest.mm

 // Copyright 2017 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.
 
 #import "ios/chrome/browser/payments/payment_request_error_view_controller.h"
 
 #include "base/mac/foundation_util.h"
 #include "components/strings/grit/components_strings.h"
 #import "ios/chrome/browser/payments/cells/payments_text_item.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_controller_test.h"
 #include "ios/chrome/grit/ios_strings.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 class PaymentRequestErrorViewControllerTest
     : public CollectionViewControllerTest {
  protected:
-  CollectionViewController* NewController() override NS_RETURNS_RETAINED {
+  CollectionViewController* InstantiateController() override {
     return [[PaymentRequestErrorViewController alloc] init];
   }
 
   PaymentRequestErrorViewController* GetPaymentRequestErrorViewController() {
     return base::mac::ObjCCastStrict<PaymentRequestErrorViewController>(
         controller());
   }
 };
 
 // Tests that the correct number of items are displayed after loading the model.
 TEST_F(PaymentRequestErrorViewControllerTest, TestModel) {
   CreateController();
   CheckController();
   CheckTitleWithId(IDS_PAYMENTS_TITLE);
 
   [GetPaymentRequestErrorViewController() loadModel];
 
   ASSERT_EQ(1, NumberOfSections());
   // There should be one item for the error message.
   ASSERT_EQ(1U, static_cast<unsigned int>(NumberOfItemsInSection(0)));
 
   // They item should be of type PriceItem.
   id item = GetCollectionViewItem(0, 0);
   EXPECT_TRUE([item isMemberOfClass:[PaymentsTextItem class]]);
 }