Adding a SQL implementation of the backing store for previews opt outs

components/previews/core/previews_io_data.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 COMPONENTS_PREVIEWS_CORE_PREVIEWS_IO_DATA_H_
 #define COMPONENTS_PREVIEWS_CORE_PREVIEWS_IO_DATA_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 20 matching lines @@
   // Stores |previews_ui_service| as |previews_ui_service_| and posts a task to
   // InitializeOnIOThread on the IO thread.
   void Initialize(base::WeakPtr<PreviewsUIService> previews_ui_service,
                   std::unique_ptr<PreviewsOptOutStore> previews_opt_out_store);
 
   PreviewsBlackList* black_list() const { return previews_black_list_.get(); }
 
  protected:
   // Posts a task to SetIOData for |previews_ui_service_| on the UI thread with
   // a weak pointer to |this|. Virtualized for testing.
-  virtual void InitializeOnIOThread(
-      std::unique_ptr<PreviewsOptOutStore> previews_opt_out_store);
+  virtual void InitializeOnIOThread();
 
  private:
   // The UI thread portion of the inter-thread communication for previews.
   base::WeakPtr<PreviewsUIService> previews_ui_service_;
 
   std::unique_ptr<PreviewsBlackList> previews_black_list_;
 
   // The UI and IO thread task runners. |ui_task_runner_| is used to post
   // tasks to |previews_ui_service_|, and |io_task_runner_| is used to post from
   // Initialize to InitializeOnIOThread as well as verify that execution is
   // happening on the IO thread.
   scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
 
   base::WeakPtrFactory<PreviewsIOData> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PreviewsIOData);
 };
 
 }  // namespace previews
 
 #endif  // COMPONENTS_PREVIEWS_CORE_PREVIEWS_IO_DATA_H_