Remove unused code

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"
 #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_actions.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_stack_item_actions.h"
-#import "ios/chrome/browser/ui/content_suggestions/cells/expandable_item.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestion.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_updater.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_commands.h"
 #include "url/gurl.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
-namespace {
-const NSTimeInterval kAnimationDuration = 0.35;
-}  // namespace
-
-@interface ContentSuggestionsViewController ()<SuggestionsStackItemActions>
+@interface ContentSuggestionsViewController ()
 
 @property(nonatomic, strong)
     ContentSuggestionsCollectionUpdater* collectionUpdater;
 
-// Expand or collapse the |cell|, if it is a ContentSuggestionsExpandableCell,
-// according to |expand|.
-- (void)expand:(BOOL)expand cell:(UICollectionViewCell*)cell;
-
 @end
 
 @implementation ContentSuggestionsViewController
 
 @synthesize suggestionCommandHandler = _suggestionCommandHandler;
 @synthesize collectionUpdater = _collectionUpdater;
 @dynamic collectionViewModel;
 
 #pragma mark - Public
 
@@ skipping 96 matching lines @@
       [self openReadingListItem:item];
       break;
     case ContentSuggestionTypeArticle:
       [self openArticle:item];
       break;
     case ContentSuggestionTypeEmpty:
       break;
   }
 }
 
-#pragma mark - ContentSuggestionsExpandableCellDelegate
-
-- (void)collapseCell:(UICollectionViewCell*)cell {
-  [self expand:NO cell:cell];
-}
-
-- (void)expandCell:(UICollectionViewCell*)cell {
-  [self expand:YES cell:cell];
-}
-
-#pragma mark - ContentSuggestionsFaviconCellDelegate
-
-- (void)openFaviconAtIndexPath:(NSIndexPath*)innerIndexPath {
-  [self.suggestionCommandHandler openFaviconAtIndex:innerIndexPath.item];
-}
-
-#pragma mark - SuggestionsStackItemActions
-
-- (void)openReadingListFirstItem:(id)sender {
-  [self.suggestionCommandHandler openFirstPageOfReadingList];
-}
-
 #pragma mark - MDCCollectionViewStylingDelegate
 
 - (UIColor*)collectionView:(nonnull UICollectionView*)collectionView
     cellBackgroundColorAtIndexPath:(nonnull NSIndexPath*)indexPath {
   if ([self.collectionUpdater
           shouldUseCustomStyleForSection:indexPath.section]) {
     return [UIColor clearColor];
   }
   return [UIColor whiteColor];
 }
@@ skipping 21 matching lines @@
                      insetForSectionAtIndex:indexPath.section];
 
   return [MDCCollectionViewCell
       cr_preferredHeightForWidth:CGRectGetWidth(collectionView.bounds) -
                                  inset.left - inset.right
                          forItem:item];
 }
 
 #pragma mark - Private
 
-- (void)expand:(BOOL)expand cell:(UICollectionViewCell*)cell {
-  NSIndexPath* indexPath = [self.collectionView indexPathForCell:cell];
-  CollectionViewItem* item =
-      [self.collectionViewModel itemAtIndexPath:indexPath];
-  if ([item conformsToProtocol:@protocol(ExpandableItem)]) {
-    id<ExpandableItem> expandableItem = (id<ExpandableItem>)item;
-
-    NSInteger sectionIdentifier = [self.collectionViewModel
-        sectionIdentifierForSection:indexPath.section];
-
-    expandableItem.expanded = expand;
-    [self reconfigureCellsForItems:@[ item ]
-           inSectionWithIdentifier:sectionIdentifier];
-
-    [UIView
-        animateWithDuration:kAnimationDuration
-                 animations:^{
-                   [self.collectionView.collectionViewLayout invalidateLayout];
-                 }];
-  }
-}
-
 // Opens the Reading List entry associated with |item|. |item| must be a
 // ContentSuggestionsReadingListItem.
 - (void)openReadingListItem:(CollectionViewItem*)item {
   ContentSuggestionsReadingListItem* readingListItem =
       base::mac::ObjCCastStrict<ContentSuggestionsReadingListItem>(item);
   [self.suggestionCommandHandler openURL:readingListItem.url];
 }
 
 // Opens the article associated with |item|. |item| must be a
 // ContentSuggestionsArticleItem.
@@ skipping 41 matching lines @@
 - (void)addEmptySectionPlaceholderIfNeeded:(NSInteger)section {
   if ([self.collectionViewModel numberOfItemsInSection:section] > 0)
     return;
 
   NSIndexPath* emptyItem =
       [self.collectionUpdater addEmptyItemForSection:section];
   [self.collectionView insertItemsAtIndexPaths:@[ emptyItem ]];
 }
 
 @end