Cleanup ContentSuggestions, removing unused functions

ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_updater.h

 // 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.
 
 #ifndef IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_COLLECTION_UPDATER_H_
 #define IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_COLLECTION_UPDATER_H_
 
 #import <UIKit/UIKit.h>
 
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestion.h"
@@ skipping 10 matching lines @@
 - (instancetype)initWithDataSource:(id<ContentSuggestionsDataSource>)dataSource
     NS_DESIGNATED_INITIALIZER;
 
 - (instancetype)init NS_UNAVAILABLE;
 
 // |collectionViewController| this Updater will update. Needs to be set before
 // adding items.
 @property(nonatomic, assign)
     ContentSuggestionsViewController* collectionViewController;
 
-// Adds a text item with a |title| and a |subtitle| in the section numbered
-// |section|. If |section| is greater than the current number of section, it
-// will add a new section at the end.
-- (void)addTextItem:(NSString*)title
-           subtitle:(NSString*)subtitle
-          toSection:(NSInteger)inputSection;
-
 // Returns whether the section should use the default, non-card style.
 - (BOOL)shouldUseCustomStyleForSection:(NSInteger)section;
 
 // Returns the ContentSuggestionType associated with this item.
 - (ContentSuggestionType)contentSuggestionTypeForItem:(CollectionViewItem*)item;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_COLLECTION_UPDATER_H_