[Offline pages] Adding ArchiveManager to abstract offline archives management

components/offline_pages/offline_page_storage_manager.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_OFFLINE_PAGES_OFFLINE_PAGE_STORAGE_MANAGER_H_
 #define COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_STORAGE_MANAGER_H_
 
 #include <stdint.h>
 
 #include <vector>
@@ skipping 18 matching lines @@
 // guaranteed to clear the pages immediately.
 //
 // OfflinePageModel should own and control the lifecycle of this manager.
 // And this manager would use OfflinePageModel to get/remove pages.
 class OfflinePageStorageManager {
  public:
   // This interface should have no knowledge of offline page model.
   // This interface should be implemented by clients managed by storage manager.
   class Client {
    public:
+    virtual ~Client() {}
+
     // Asks the client to get all offline pages and invoke |callback|.
     virtual void GetAllPages(
         const MultipleOfflinePageItemCallback& callback) = 0;
 
     // Asks the client to delete pages based on |offline_ids| and invoke
     // |callback|.
     virtual void DeletePagesByOfflineId(const std::vector<int64_t>& offline_ids,
                                         const DeletePageCallback& callback) = 0;
   };
 
@@ skipping 47 matching lines @@
   std::unique_ptr<base::Clock> clock_;
 
   base::WeakPtrFactory<OfflinePageStorageManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(OfflinePageStorageManager);
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_STORAGE_MANAGER_H_