[Payment Request] Refactors the remaining selector view controllers

ios/chrome/browser/payments/shipping_address_selection_coordinator.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/shipping_address_selection_coordinator.h"
 
 #include "base/strings/sys_string_conversions.h"
 #include "components/autofill/core/browser/autofill_profile.h"
 #include "components/payments/core/strings_util.h"
 #include "ios/chrome/browser/payments/payment_request.h"
 #include "ios/chrome/browser/payments/payment_request_selector_view_controller.h"
 #import "ios/chrome/browser/payments/payment_request_util.h"
 #include "ios/chrome/browser/payments/shipping_address_selection_mediator.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 namespace {
 using ::payment_request_util::GetShippingAddressSelectorErrorMessage;
 using ::payments::GetShippingAddressSectionString;
 using ::payments::GetShippingAddressSelectorInfoMessage;
+
+// The delay in nano seconds before notifying the delegate of the selection.
+const int64_t kDelegateNotificationDelayInNanoSeconds = 0.2 * NSEC_PER_SEC;
 }  // namespace
 
 @interface ShippingAddressSelectionCoordinator ()
 
 @property(nonatomic, strong)
     PaymentRequestSelectorViewController* viewController;
 
 @property(nonatomic, strong) ShippingAddressSelectionMediator* mediator;
 
 // Called when the user selects a shipping address. The cell is checked, the
@@ skipping 76 matching lines @@
   // TODO(crbug.com/602666): Present a shipping address addition UI.
 }
 
 #pragma mark - Helper methods
 
 - (void)delayedNotifyDelegateOfSelection:
     (autofill::AutofillProfile*)shippingAddress {
   self.viewController.view.userInteractionEnabled = NO;
   __weak ShippingAddressSelectionCoordinator* weakSelf = self;
   dispatch_after(
-      dispatch_time(DISPATCH_TIME_NOW,
-                    static_cast<int64_t>(0.2 * NSEC_PER_SEC)),
+      dispatch_time(DISPATCH_TIME_NOW, kDelegateNotificationDelayInNanoSeconds),
       dispatch_get_main_queue(), ^{
         [weakSelf.mediator setState:PaymentRequestSelectorStatePending];
         [weakSelf.viewController loadModel];
-        [[weakSelf.viewController collectionView] reloadData];
+        [weakSelf.viewController.collectionView reloadData];
 
         [weakSelf.delegate shippingAddressSelectionCoordinator:weakSelf
                                       didSelectShippingAddress:shippingAddress];
       });
 }
 
 @end