Remove categories notified as invalid

ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_updater.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_collection_updater.h"
 
 #include "base/logging.h"
 #include "base/mac/foundation_util.h"
 #include "base/time/time.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_controller.h"
@@ skipping 170 matching lines @@
     articleItem.suggestionIdentifier = suggestion.suggestionIdentifier;
 
     [model addItem:articleItem toSectionWithIdentifier:sectionIdentifier];
   }
 
   if ([self.collectionViewController isViewLoaded]) {
     [self.collectionViewController.collectionView reloadData];
   }
 }
 
+- (void)clearSection:(ContentSuggestionsSectionInformation*)sectionInfo {
+  SectionIdentifier sectionIdentifier = SectionIdentifierForInfo(sectionInfo);
+  NSInteger section = [self.collectionViewController.collectionViewModel
+      sectionIdentifierForSection:sectionIdentifier];
+
+  [self.collectionViewController dismissSection:section];
+}
+
 #pragma mark - Public methods
 
 - (BOOL)shouldUseCustomStyleForSection:(NSInteger)section {
   NSNumber* identifier = @([self.collectionViewController.collectionViewModel
       sectionIdentifierForSection:section]);
   ContentSuggestionsSectionInformation* sectionInformation =
       self.sectionInfoBySectionIdentifier[identifier];
   return sectionInformation.layout == ContentSuggestionsSectionLayoutCustom;
 }
 
@@ skipping 49 matching lines @@
   }
   return sectionIdentifier;
 }
 
 - (void)resetModels {
   [self.collectionViewController loadModel];
   self.sectionInfoBySectionIdentifier = [[NSMutableDictionary alloc] init];
 }
 
 @end