[Payment Request] Unit tests for incomplete shipping/billing address selection

ios/chrome/browser/payments/test_payment_request.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/test_payment_request.h"
 
 #include "components/autofill/core/browser/personal_data_manager.h"
 #include "components/autofill/core/browser/region_data_loader.h"
 #include "components/payments/core/payments_profile_comparator.h"
 #include "ios/web/public/payments/payment_request.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 void TestPaymentRequest::ClearShippingProfiles() {
   shipping_profiles_.clear();
 }
 
 void TestPaymentRequest::ClearContactProfiles() {
   contact_profiles_.clear();
 }
 
 void TestPaymentRequest::ClearCreditCards() {
   credit_cards_.clear();
 }
 
 autofill::RegionDataLoader* TestPaymentRequest::GetRegionDataLoader() {
-  return region_data_loader_;
+  if (region_data_loader_)
+    return region_data_loader_;
+  return PaymentRequest::GetRegionDataLoader();
 }
 
 payments::PaymentsProfileComparator* TestPaymentRequest::profile_comparator() {
-  return profile_comparator_;
+  if (profile_comparator_)
+    return profile_comparator_;
+  return PaymentRequest::profile_comparator();
 }