Cleanup ContentSuggestions, removing unused functions

ios/chrome/browser/ui/content_suggestions/content_suggestions_view_controller.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_VIEW_CONTROLLER_H_
 #define IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_VIEW_CONTROLLER_H_
 
 #import <UIKit/UIKit.h>
 
 #import "ios/chrome/browser/ui/collection_view/collection_view_controller.h"
@@ skipping 12 matching lines @@
                    dataSource:(id<ContentSuggestionsDataSource>)dataSource
     NS_DESIGNATED_INITIALIZER;
 
 - (instancetype)initWithStyle:(CollectionViewControllerStyle)style
     NS_UNAVAILABLE;
 
 // Handler for the commands sent by the ContentSuggestionsViewController.
 @property(nonatomic, weak) id<ContentSuggestionsCommands>
     suggestionCommandHandler;
 
-// 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;
-
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_VIEW_CONTROLLER_H_