delete the levelDB storage implementation.

components/offline_pages/offline_page_metadata_store_impl.h

-// Copyright 2015 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_METADATA_STORE_IMPL_H_
-#define COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_METADATA_STORE_IMPL_H_
-
-#include <stdint.h>
-
-#include <vector>
-
-#include "base/files/file_path.h"
-#include "base/gtest_prod_util.h"
-#include "base/macros.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/weak_ptr.h"
-#include "components/leveldb_proto/proto_database.h"
-#include "components/offline_pages/offline_page_metadata_store.h"
-
-namespace base {
-class SequencedTaskRunner;
-}
-
-namespace offline_pages {
-
-class OfflinePageEntry;
-
-// Implements OfflinePageMetadataStore using leveldb_proto::ProtoDatabase
-// component. Stores metadata of offline pages as serialized protobufs in a
-// LevelDB key/value pairs.
-// Underlying implementation guarantees that all of the method calls will be
-// executed sequentially, and started operations will finish even after the
-// store is already destroyed (callbacks will be called).
-class OfflinePageMetadataStoreImpl : public OfflinePageMetadataStore {
- public:
-  OfflinePageMetadataStoreImpl(
-      scoped_refptr<base::SequencedTaskRunner> background_task_runner,
-      const base::FilePath& database_dir);
-  ~OfflinePageMetadataStoreImpl() override;
-
-  // OfflinePageMetadataStore implementation:
-  void Load(const LoadCallback& callback) override;
-  void AddOrUpdateOfflinePage(const OfflinePageItem& offline_page_record,
-                              const UpdateCallback& callback) override;
-  void RemoveOfflinePages(const std::vector<int64_t>& offline_ids,
-                          const UpdateCallback& callback) override;
-  void Reset(const ResetCallback& callback) override;
-
- private:
-  friend class OfflinePageMetadataStoreImplTest;
-
-  void LoadContinuation(const LoadCallback& callback, bool success);
-  void LoadDone(const LoadCallback& callback,
-                bool success,
-                std::unique_ptr<std::vector<OfflinePageEntry>> entries);
-  void NotifyLoadResult(const LoadCallback& callback,
-                        LoadStatus status,
-                        const std::vector<OfflinePageItem>& result);
-
-  // Implements the update.
-  void UpdateEntries(std::unique_ptr<leveldb_proto::ProtoDatabase<
-                         OfflinePageEntry>::KeyEntryVector> entries_to_save,
-                     std::unique_ptr<std::vector<std::string>> keys_to_remove,
-                     const UpdateCallback& callback);
-
-  void UpdateDone(const OfflinePageMetadataStore::UpdateCallback& callback,
-                  bool success);
-
-  void ResetDone(const ResetCallback& callback, bool success);
-
-  // Called when a database has to be migrated from old bookmark ids
-  // to new offline ids.
-  // TODO(bburns): Perhaps remove this eventually?
-  void DatabaseUpdateDone(const OfflinePageMetadataStore::LoadCallback& cb,
-                          LoadStatus status,
-                          const std::vector<OfflinePageItem>& result,
-                          bool success);
-
-  scoped_refptr<base::SequencedTaskRunner> background_task_runner_;
-  base::FilePath database_dir_;
-  std::unique_ptr<leveldb_proto::ProtoDatabase<OfflinePageEntry>> database_;
-
-  base::WeakPtrFactory<OfflinePageMetadataStoreImpl> weak_ptr_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(OfflinePageMetadataStoreImpl);
-};
-
-}  // namespace offline_pages
-
-#endif  // COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_METADATA_STORE_IMPL_H_