Allow CollectionViewModel/Controller queries without SectionIdentifier

ios/chrome/browser/ui/payments/payment_request_view_controller.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/ui/payments/payment_request_view_controller.h"
 
 #include "base/mac/foundation_util.h"
 
 #include "base/strings/stringprintf.h"
 #include "base/strings/sys_string_conversions.h"
@@ skipping 390 matching lines @@
   self.styler.cellStyle = MDCCollectionViewCellStyleCard;
   self.styler.separatorInset =
       UIEdgeInsetsMake(0, kSeparatorEdgeInset, 0, kSeparatorEdgeInset);
 }
 
 - (void)updatePaymentSummaryWithTotalValueChanged:(BOOL)totalValueChanged {
   [self fillPaymentSummaryItem:_paymentSummaryItem
                withPaymentItem:_paymentRequest->payment_details().total
          withTotalValueChanged:totalValueChanged];
   NSIndexPath* indexPath =
-      [self.collectionViewModel indexPathForItem:_paymentSummaryItem
-                         inSectionWithIdentifier:SectionIdentifierSummary];
+      [self.collectionViewModel indexPathForItem:_paymentSummaryItem];
   [self.collectionView reloadItemsAtIndexPaths:@[ indexPath ]];
 }
 
 - (void)updateSelectedShippingAddressUI {
   [self fillShippingAddressItem:_selectedShippingAddressItem
             withAutofillProfile:_paymentRequest->selected_shipping_profile()];
   NSIndexPath* indexPath =
-      [self.collectionViewModel indexPathForItem:_selectedShippingAddressItem
-                         inSectionWithIdentifier:SectionIdentifierShipping];
+      [self.collectionViewModel indexPathForItem:_selectedShippingAddressItem];
   [self.collectionView reloadItemsAtIndexPaths:@[ indexPath ]];
 }
 
 - (void)updateSelectedShippingOptionUI {
   [self fillShippingOptionItem:_selectedShippingOptionItem
                     withOption:_paymentRequest->selected_shipping_option()];
   NSIndexPath* indexPath =
-      [self.collectionViewModel indexPathForItem:_selectedShippingOptionItem
-                         inSectionWithIdentifier:SectionIdentifierShipping];
+      [self.collectionViewModel indexPathForItem:_selectedShippingOptionItem];
   [self.collectionView reloadItemsAtIndexPaths:@[ indexPath ]];
 }
 
 - (void)updateSelectedPaymentMethodUI {
   [self fillPaymentMethodItem:_selectedPaymentMethodItem
                withCreditCard:_paymentRequest->selected_credit_card()];
   NSIndexPath* indexPath =
-      [self.collectionViewModel indexPathForItem:_selectedPaymentMethodItem
-                         inSectionWithIdentifier:SectionIdentifierPayment];
+      [self.collectionViewModel indexPathForItem:_selectedPaymentMethodItem];
   [self.collectionView reloadItemsAtIndexPaths:@[ indexPath ]];
 }
 
 #pragma mark - Helper methods
 
 - (void)fillPaymentSummaryItem:(PriceItem*)item
                withPaymentItem:(web::PaymentItem)paymentItem
          withTotalValueChanged:(BOOL)totalValueChanged {
   item.item =
       base::SysUTF16ToNSString(_paymentRequest->payment_details().total.label);
@@ skipping 175 matching lines @@
 
 - (BOOL)collectionView:(UICollectionView*)collectionView
     shouldHideItemBackgroundAtIndexPath:(NSIndexPath*)indexPath {
   // No background on the footer text item.
   NSInteger sectionIdentifier =
       [self.collectionViewModel sectionIdentifierForSection:indexPath.section];
   return sectionIdentifier == SectionIdentifierFooter ? YES : NO;
 }
 
 @end