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

ios/chrome/browser/payments/payment_items_display_view_controller_unittest.mm

 // 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.
 
 #import "ios/chrome/browser/payments/payment_items_display_view_controller.h"
 
 #include "base/mac/foundation_util.h"
 #include "base/memory/ptr_util.h"
 #include "components/autofill/core/browser/test_personal_data_manager.h"
 #import "ios/chrome/browser/payments/cells/price_item.h"
 #include "ios/chrome/browser/payments/payment_request.h"
 #import "ios/chrome/browser/payments/payment_request_test_util.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_controller_test.h"
 #include "ios/chrome/grit/ios_strings.h"
 #include "ios/web/public/payments/payment_request.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 class PaymentItemsDisplayViewControllerTest
     : public CollectionViewControllerTest {
  protected:
   CollectionViewController* NewController() override NS_RETURNS_RETAINED {
     personal_data_manager_ =
         base::MakeUnique<autofill::TestPersonalDataManager>();
 
     web::PaymentRequest web_payment_request =
         payment_request_test_util::CreateTestWebPaymentRequest();
 
@@ skipping 26 matching lines @@
   ASSERT_EQ(1, NumberOfSections());
   // There should be one item for the total and another one for sub-total.
   ASSERT_EQ(2U, static_cast<unsigned int>(NumberOfItemsInSection(0)));
 
   // They both should be of type PriceItem.
   id item = GetCollectionViewItem(0, 0);
   EXPECT_TRUE([item isMemberOfClass:[PriceItem class]]);
   item = GetCollectionViewItem(0, 1);
   EXPECT_TRUE([item isMemberOfClass:[PriceItem class]]);
 }