Remove unused code

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/strings/sys_string_conversions.h"
 #include "base/time/time.h"
 #include "components/strings/grit/components_strings.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_text_item.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_controller.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
 #import "ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_article_item.h"
-#import "ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_button_item.h"
-#import "ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_expandable_item.h"
-#import "ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_favicon_item.h"
 #import "ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_footer_item.h"
 #import "ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_reading_list_item.h"
-#import "ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_stack_item.h"
 #import "ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_text_item.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestion.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_data_sink.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_data_source.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_image_fetcher.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_view_controller.h"
 #import "ios/chrome/browser/ui/content_suggestions/identifier/content_suggestion_identifier.h"
 #import "ios/chrome/browser/ui/content_suggestions/identifier/content_suggestions_section_information.h"
 #import "ios/chrome/browser/ui/favicon/favicon_attributes.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "url/gurl.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 namespace {
 
 using CSCollectionViewItem =
     CollectionViewItem<ContentSuggestionIdentification>;
 using CSCollectionViewModel = CollectionViewModel<CSCollectionViewItem*>;
 
 // Enum defining the ItemType of this ContentSuggestionsCollectionUpdater.
 typedef NS_ENUM(NSInteger, ItemType) {
-  ItemTypeText = kItemTypeEnumZero,
-  ItemTypeArticle,
-  ItemTypeExpand,
-  ItemTypeStack,
-  ItemTypeFavicon,
+  ItemTypeArticle = kItemTypeEnumZero,
   ItemTypeFooter,
   ItemTypeHeader,
   ItemTypeEmpty,
   ItemTypeReadingList,
 };
 
 typedef NS_ENUM(NSInteger, SectionIdentifier) {
-  SectionIdentifierBookmarks = kSectionIdentifierEnumZero,
-  SectionIdentifierArticles,
+  SectionIdentifierArticles = kSectionIdentifierEnumZero,
   SectionIdentifierReadingList,
   SectionIdentifierDefault,
 };
 
 // Update ContentSuggestionTypeForItemType if you update this function.
 ItemType ItemTypeForContentSuggestionType(ContentSuggestionType type) {
   switch (type) {
     case ContentSuggestionTypeArticle:
       return ItemTypeArticle;
     case ContentSuggestionTypeEmpty:
@@ skipping 13 matching lines @@
   // Add new type here
 
   // Default type.
   return ContentSuggestionTypeEmpty;
 }
 
 // Returns the section identifier corresponding to the section |info|.
 SectionIdentifier SectionIdentifierForInfo(
     ContentSuggestionsSectionInformation* info) {
   switch (info.sectionID) {
-    case ContentSuggestionsSectionBookmarks:
-      return SectionIdentifierBookmarks;
-
     case ContentSuggestionsSectionArticles:
       return SectionIdentifierArticles;
 
     case ContentSuggestionsSectionReadingList:
       return SectionIdentifierReadingList;
 
     case ContentSuggestionsSectionUnknown:
       return SectionIdentifierDefault;
   }
 }
@@ skipping 406 matching lines @@
         [model sectionIdentifierForSection:sectionNumber];
     if ([model hasItem:item inSectionWithIdentifier:sectionIdentifier]) {
       [self.collectionViewController
           reconfigureCellsForItems:@[ item ]
            inSectionWithIdentifier:sectionIdentifier];
     }
   }
 }
 
 @end