Remove suggestions 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 111 matching lines @@
 
   [self reloadData];
 }
 
 #pragma mark - ContentSuggestionsDataSink
 
 - (void)dataAvailable {
   [self reloadData];
 }
 
+- (void)clearSuggestion:(ContentSuggestionIdentifier*)suggestionIdentifier {
+  SectionIdentifier sectionIdentifier =
+      SectionIdentifierForInfo(suggestionIdentifier.sectionInfo);
+  if (![self.collectionViewController.collectionViewModel
+          hasSectionForSectionIdentifier:sectionIdentifier]) {
+    return;
+  }
+
+  NSArray<CollectionViewItem<ContentSuggestionIdentification>*>*
+      itemsInSection = [self.collectionViewController.collectionViewModel
+          itemsInSectionWithIdentifier:sectionIdentifier];
+
+  CollectionViewItem<ContentSuggestionIdentification>* correspondingItem = nil;
+  for (CollectionViewItem<ContentSuggestionIdentification>* item in
+           itemsInSection) {
+    if (item.suggestionIdentifier == suggestionIdentifier) {
+      correspondingItem = item;
+      break;
+    }
+  }
+
+  if (!correspondingItem)
+    return;
+
+  NSIndexPath* indexPath = [self.collectionViewController.collectionViewModel
+             indexPathForItem:correspondingItem
+      inSectionWithIdentifier:sectionIdentifier];
+  [self.collectionViewController dismissEntryAtIndexPath:indexPath];
+}
+
 #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 80 matching lines @@
   }
   return sectionIdentifier;
 }
 
 - (void)resetModels {
   [self.collectionViewController loadModel];
   self.sectionInfoBySectionIdentifier = [[NSMutableDictionary alloc] init];
 }
 
 @end