Remove categories notified as invalid

ios/chrome/browser/ui/content_suggestions/content_suggestions_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/content_suggestions/content_suggestions_view_controller.h"
 
 #include "base/mac/foundation_util.h"
 #import "ios/chrome/browser/ui/collection_view/cells/MDCCollectionViewCell+Chrome.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_item.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
@@ skipping 48 matching lines @@
     return;
   }
 
   [self.collectionView performBatchUpdates:^{
     [self collectionView:self.collectionView
         willDeleteItemsAtIndexPaths:@[ indexPath ]];
 
     [self.collectionView deleteItemsAtIndexPaths:@[ indexPath ]];
   }
       completion:^(BOOL) {
-        // The context menu could be displayed for the delete entry.
+        // The context menu could be displayed for the deleted entry.
         [self.suggestionCommandHandler dismissContextMenu];
       }];
 }
+
+- (void)dismissSection:(NSInteger)section {
+  if (section >= [self numberOfSectionsInCollectionView:self.collectionView]) {
+    return;
+  }
+
+  NSInteger sectionIdentifier =
+      [self.collectionViewModel sectionIdentifierForSection:section];
+
+  [self.collectionView performBatchUpdates:^{
+    [self.collectionViewModel removeSectionWithIdentifier:sectionIdentifier];
+    [self.collectionView deleteSections:[NSIndexSet indexSetWithIndex:section]];
+  }
+      completion:^(BOOL) {
+        // The context menu could be displayed for the deleted entries.
+        [self.suggestionCommandHandler dismissContextMenu];
+      }];
+}
 
 #pragma mark - UIViewController
 
 - (void)viewDidLoad {
   [super viewDidLoad];
 
   _collectionUpdater.collectionViewController = self;
 
   self.collectionView.delegate = self;
   self.styler.cellStyle = MDCCollectionViewCellStyleCard;
@@ skipping 134 matching lines @@
   ContentSuggestionsArticleItem* articleItem =
       base::mac::ObjCCastStrict<ContentSuggestionsArticleItem>(touchedItem);
 
   [self.suggestionCommandHandler
       displayContextMenuForArticle:articleItem
                            atPoint:touchLocation
                        atIndexPath:touchedItemIndexPath];
 }
 
 @end