Migrate data from old localstorage format to new format.

content/browser/dom_storage/local_storage_context_mojo.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 CONTENT_BROWSER_DOM_STORAGE_LOCAL_STORAGE_CONTEXT_MOJO_H_
 #define CONTENT_BROWSER_DOM_STORAGE_LOCAL_STORAGE_CONTEXT_MOJO_H_
 
 #include <memory>
 
 #include "base/files/file_path.h"
 #include "content/common/content_export.h"
 #include "content/common/leveldb_wrapper.mojom.h"
 #include "services/file/public/interfaces/file_system.mojom.h"
 #include "url/origin.h"
 
 namespace service_manager {
 class Connection;
 class Connector;
 }
 
 namespace content {
 
+class DOMStorageTaskRunner;
 class LevelDBWrapperImpl;
 struct LocalStorageUsageInfo;
 
 // Used for mojo-based LocalStorage implementation (behind --mojo-local-storage
 // for now).
 class CONTENT_EXPORT LocalStorageContextMojo {
  public:
   using GetStorageUsageCallback =
       base::OnceCallback<void(std::vector<LocalStorageUsageInfo>)>;
 
   LocalStorageContextMojo(service_manager::Connector* connector,
+                          scoped_refptr<DOMStorageTaskRunner> task_runner,
+                          const base::FilePath& old_localstorage_path,
                           const base::FilePath& subdirectory);
   ~LocalStorageContextMojo();
 
   void OpenLocalStorage(const url::Origin& origin,
                         mojom::LevelDBWrapperRequest request);
   void GetStorageUsage(GetStorageUsageCallback callback);
   void DeleteStorage(const url::Origin& origin);
   // Like DeleteStorage(), but also deletes storage for all sub-origins.
   void DeleteStorageForPhysicalOrigin(const url::Origin& origin);
   void Flush();
 
   leveldb::mojom::LevelDBDatabaseAssociatedRequest DatabaseRequestForTesting();
 
  private:
+  class LevelDBWrapperHolder;
+
   // Runs |callback| immediately if already connected to a database, otherwise
   // delays running |callback| untill after a connection has been established.
   // Initiates connecting to the database if no connection is in progres yet.
   void RunWhenConnected(base::OnceClosure callback);
 
-  void OnLevelDBWrapperHasNoBindings(const url::Origin& origin);
-  std::vector<leveldb::mojom::BatchedOperationPtr>
-  OnLevelDBWrapperPrepareToCommit(const url::Origin& origin,
-                                  const LevelDBWrapperImpl& wrapper);
   void OnUserServiceConnectionComplete();
   void OnUserServiceConnectionError();
 
   // Part of our asynchronous directory opening called from RunWhenConnected().
   void InitiateConnection(bool in_memory_only = false);
   void OnDirectoryOpened(filesystem::mojom::FileError err);
   void OnDatabaseOpened(leveldb::mojom::DatabaseError status);
   void OnGotDatabaseVersion(leveldb::mojom::DatabaseError status,
                             const std::vector<uint8_t>& value);
   void OnConnectionFinished();
@@ skipping 33 matching lines @@
   file::mojom::FileSystemPtr file_system_;
   filesystem::mojom::DirectoryPtr directory_;
 
   leveldb::mojom::LevelDBServicePtr leveldb_service_;
   leveldb::mojom::LevelDBDatabaseAssociatedPtr database_;
   bool tried_to_recreate_ = false;
 
   std::vector<base::OnceClosure> on_database_opened_callbacks_;
 
   // Maps between an origin and its prefixed LevelDB view.
-  std::map<url::Origin, std::unique_ptr<LevelDBWrapperImpl>> level_db_wrappers_;
+  std::map<url::Origin, std::unique_ptr<LevelDBWrapperHolder>>
+      level_db_wrappers_;
+
+  // Used to access old data for migration.
+  scoped_refptr<DOMStorageTaskRunner> task_runner_;
+  base::FilePath old_localstorage_path_;
 
   base::WeakPtrFactory<LocalStorageContextMojo> weak_ptr_factory_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOM_STORAGE_LOCAL_STORAGE_CONTEXT_MOJO_H_