Download Service : Added leveldb proto layer

components/download/internal/store.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 COMPONENTS_DOWNLOAD_INTERNAL_STORE_H_
 #define COMPONENTS_DOWNLOAD_INTERNAL_STORE_H_
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
-#include "base/memory/ref_counted.h"
-#include "base/sequenced_task_runner.h"
 
 namespace download {
 
 struct Entry;
 
 // A backing storage interface responsible for persisting Entry objects.
 class Store {
  public:
   using InitCallback =
-      base::OnceCallback<void(bool success,
-                              std::unique_ptr<std::vector<Entry>> entries)>;
-  using StoreCallback = base::OnceCallback<void(bool success)>;
+      base::Callback<void(bool success,
+                          std::unique_ptr<std::vector<Entry>> entries)>;
+  using StoreCallback = base::Callback<void(bool success)>;
 
   virtual ~Store() = default;
 
   // Returns whether or not this Store is initialized and can be interracted
   // with.
   virtual bool IsInitialized() = 0;
 
   // Initializes this Store and asynchronously returns whether or not that
   // initialization was successful as well as a list of Entry objects from the
   // Store.
-  virtual void Initialize(InitCallback callback) = 0;
+  virtual void Initialize(const InitCallback& callback) = 0;
 
   // Destroyes the store and asynchronously returns whether or not that
   // destruction was successful.
-  virtual void Destroy(StoreCallback callback) = 0;
+  virtual void Destroy(const StoreCallback& callback) = 0;
 
   // Adds or updates |entry| in this Store asynchronously and returns whether or
   // not that was successful.
-  virtual void Update(const Entry& entry, StoreCallback callback) = 0;
+  virtual void Update(const Entry& entry, const StoreCallback& callback) = 0;
 
   // Removes the Entry associated with |guid| from this Store asynchronously and
   // returns whether or not that was successful.
-  virtual void Remove(const std::string& guid, StoreCallback callback) = 0;
+  virtual void Remove(const std::string& guid,
+                      const StoreCallback& callback) = 0;
 };
 
 }  // namespace download
 
 #endif  // COMPONENTS_DOWNLOAD_INTERNAL_STORE_H_