Move ReadingList model to components/reading_list/core

ios/chrome/browser/reading_list/reading_list_remover_helper.h

 // Copyright 2017 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_READING_LIST_READING_LIST_REMOVER_HELPER_H_
 #define IOS_CHROME_BROWSER_READING_LIST_READING_LIST_REMOVER_HELPER_H_
 
 #include "base/callback.h"
 #include "base/scoped_observer.h"
-#include "components/reading_list/ios/reading_list_model_observer.h"
+#include "components/reading_list/core/reading_list_model_observer.h"
 
 namespace ios {
 class ChromeBrowserState;
 }
 
 class ReadingListModel;
 class ReadingListDownloadService;
 
 namespace reading_list {
 class ReadingListRemoverHelper : public ReadingListModelObserver {
@@ skipping 14 matching lines @@
   Callback completion_;
   ReadingListModel* reading_list_model_;
   ReadingListDownloadService* reading_list_download_service_;
   ScopedObserver<ReadingListModel, ReadingListModelObserver> scoped_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(ReadingListRemoverHelper);
 };
 }  // namespace reading_list
 
 #endif  // IOS_CHROME_BROWSER_READING_LIST_READING_LIST_REMOVER_HELPER_H_