[Offline] Creates metadata store interface for offline pages

components/offline_pages/offline_page_metadata_store_impl.h

Index: components/offline_pages/offline_page_metadata_store_impl.h
diff --git a/components/offline_pages/offline_page_metadata_store_impl.h b/components/offline_pages/offline_page_metadata_store_impl.h
new file mode 100644
index 0000000000000000000000000000000000000000..848b25843e5af54764e6cdcf3d82f7d6e8d6bce6
--- /dev/null
+++ b/components/offline_pages/offline_page_metadata_store_impl.h
@@ -0,0 +1,47 @@
+// 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 "components/offline_pages/offline_page_metadata_store.h"
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+
+namespace base {
+class FilePath;
+class SequencedTaskRunner;
+}
+
+namespace offline_pages {
+
+// Implements OfflinePageMetadataStore using SQLite.
+class OfflinePageMetadataStoreImpl : public OfflinePageMetadataStore {
+ public:
+  OfflinePageMetadataStoreImpl(
+      const base::FilePath& path,
+      scoped_refptr<base::SequencedTaskRunner> blocking_task_runner);
+  ~OfflinePageMetadataStoreImpl() override;
+
+  void Close();
+
+  // OfflinePageMetadataStore implementation:
+  void Load(const LoadCallback& callback) override;
+  void AddOfflinePage(const OfflinePageItem& offline_page_record,
+                      const UpdateCallback& callback) override;
+  void RemoveOfflinePage(const GURL& page_url,
+                         const UpdateCallback& callback) override;
+  void Destroy(const UpdateCallback& callback) override;
+
+ private:
+  class Backend;
+
+  scoped_refptr<Backend> backend_;
+  scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
+};
+
+}  // namespace offline_pages
+
+#endif  // COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_METADATA_STORE_IMPL_H_