ContentSuggestions collection adds items with animation

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 71 matching lines @@
   [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];
       }];
 }
 
+- (void)addSuggestions:(NSArray<ContentSuggestion*>*)suggestions {
+  if (suggestions.count == 0) {
+    return;
+  }
+
+  [self.collectionView performBatchUpdates:^{
+    NSIndexSet* addedSections =
+        [self.collectionUpdater addSectionsForSuggestionsToModel:suggestions];
+    [self.collectionView insertSections:addedSections];
+  }
+                                completion:nil];
+
+  [self.collectionView performBatchUpdates:^{
+    NSArray<NSIndexPath*>* addedItems =
+        [self.collectionUpdater addSuggestionsToModel:suggestions];
+    [self.collectionView insertItemsAtIndexPaths:addedItems];
+  }
+                                completion:nil];
+}
+
 #pragma mark - UIViewController
 
 - (void)viewDidLoad {
   [super viewDidLoad];
 
   _collectionUpdater.collectionViewController = self;
 
   self.collectionView.delegate = self;
   self.styler.cellStyle = MDCCollectionViewCellStyleCard;
 
@@ skipping 133 matching lines @@
   ContentSuggestionsArticleItem* articleItem =
       base::mac::ObjCCastStrict<ContentSuggestionsArticleItem>(touchedItem);
 
   [self.suggestionCommandHandler
       displayContextMenuForArticle:articleItem
                            atPoint:touchLocation
                        atIndexPath:touchedItemIndexPath];
 }
 
 @end