Move ReadingList model to components/reading_list/core

ios/chrome/browser/ui/reading_list/reading_list_menu_notifier.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/reading_list/reading_list_menu_notifier.h"
 
 #include <memory>
 
-#include "components/reading_list/ios/reading_list_model.h"
+#include "components/reading_list/core/reading_list_model.h"
 #import "ios/chrome/browser/ui/reading_list/reading_list_menu_notification_delegate.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 class ReadingListObserverBridge;
 
 @interface ReadingListMenuNotifier () {
   // Observer for reading list changes.
@@ skipping 71 matching lines @@
 
 - (NSInteger)readingListUnreadCount {
   return _readingListModel->unread_size();
 }
 
 - (BOOL)readingListUnseenItemsExist {
   return _readingListModel->unseen_size() > 0;
 }
 
 @end