Add MostVistedSites to ContentSuggestionsMediator

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 117 matching lines @@
 
   CollectionViewItem* item =
       [self.collectionViewModel itemAtIndexPath:indexPath];
   switch ([self.collectionUpdater contentSuggestionTypeForItem:item]) {
     case ContentSuggestionTypeReadingList:
       [self openReadingListItem:item];
       break;
     case ContentSuggestionTypeArticle:
       [self openArticle:item];
       break;
+    case ContentSuggestionTypeMostVisited:
+      // TODO(crbug.com/707754): Open the most visited site.
+      break;
     case ContentSuggestionTypeEmpty:
       break;
   }
 }
 
 #pragma mark - MDCCollectionViewStylingDelegate
 
 - (UIColor*)collectionView:(nonnull UICollectionView*)collectionView
     cellBackgroundColorAtIndexPath:(nonnull NSIndexPath*)indexPath {
   if ([self.collectionUpdater
@@ skipping 87 matching lines @@
 - (void)addEmptySectionPlaceholderIfNeeded:(NSInteger)section {
   if ([self.collectionViewModel numberOfItemsInSection:section] > 0)
     return;
 
   NSIndexPath* emptyItem =
       [self.collectionUpdater addEmptyItemForSection:section];
   [self.collectionView insertItemsAtIndexPaths:@[ emptyItem ]];
 }
 
 @end