Use CollectionViewTextItem instead of a cast

ios/chrome/browser/ui/settings/block_popups_collection_view_controller.mm

 // Copyright 2015 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/settings/block_popups_collection_view_controller.h"
 
 #import "base/ios/weak_nsobject.h"
 #include "base/logging.h"
 #import "base/mac/foundation_util.h"
 #import "base/mac/scoped_nsobject.h"
@@ skipping 128 matching lines @@
       ItemTypeMainSwitch) {
     CollectionViewSwitchCell* switchCell =
         base::mac::ObjCCastStrict<CollectionViewSwitchCell>(cell);
     [switchCell.switchView addTarget:self
                               action:@selector(blockPopupsSwitchChanged:)
                     forControlEvents:UIControlEventValueChanged];
   }
   return cell;
 }
 
-- (UICollectionReusableView*)collectionView:(UICollectionView*)collectionView
-          viewForSupplementaryElementOfKind:(NSString*)kind
-                                atIndexPath:(NSIndexPath*)indexPath {
-  UICollectionReusableView* view = [super collectionView:collectionView
-                       viewForSupplementaryElementOfKind:kind
-                                             atIndexPath:indexPath];
-  MDCCollectionViewTextCell* textCell =
-      base::mac::ObjCCast<MDCCollectionViewTextCell>(view);
-  if (textCell) {
-    textCell.textLabel.textColor = [[MDCPalette greyPalette] tint500];
-  }
-  return view;
-};
-
 #pragma mark - MDCCollectionViewEditingDelegate
 
 - (BOOL)collectionView:(UICollectionView*)collectionView
     canEditItemAtIndexPath:(NSIndexPath*)indexPath {
   // Any item in SectionIdentifierExceptions is editable.
   return [self.collectionViewModel
              sectionIdentifierForSection:indexPath.section] ==
          SectionIdentifierExceptions;
 }
 
@@ skipping 131 matching lines @@
   }
 }
 
 - (void)populateExceptionsItems {
   CollectionViewModel* model = self.collectionViewModel;
   [model addSectionWithIdentifier:SectionIdentifierExceptions];
 
   CollectionViewTextItem* header = [
       [[CollectionViewTextItem alloc] initWithType:ItemTypeHeader] autorelease];
   header.text = l10n_util::GetNSString(IDS_IOS_POPUPS_ALLOWED);
+  header.textColor = [[MDCPalette greyPalette] tint500];
   [model setHeader:header forSectionWithIdentifier:SectionIdentifierExceptions];
 
   for (size_t i = 0; i < _exceptions.GetSize(); ++i) {
     std::string allowed_url;
     _exceptions.GetString(i, &allowed_url);
     CollectionViewTextItem* item = [[[CollectionViewTextItem alloc]
         initWithType:ItemTypeException] autorelease];
     item.text = base::SysUTF8ToNSString(allowed_url);
     [model addItem:item toSectionWithIdentifier:SectionIdentifierExceptions];
   }
@@ skipping 33 matching lines @@
       [[strongSelf collectionViewModel]
           removeSectionWithIdentifier:SectionIdentifierExceptions];
       [[strongSelf collectionView]
           deleteSections:[NSIndexSet indexSetWithIndex:index]];
     }
                                   completion:nil];
   }
 }
 
 @end