[Offline Pages] Set up the initial prefetching service.

components/offline_pages/core/prefetch/prefetch_service_impl.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_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_SERVICE_IMPL_H_
+#define COMPONENTS_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_SERVICE_IMPL_H_
+
+#include <vector>
+
+#include "components/offline_pages/core/prefetch/prefetch_service.h"
+#include "url/gurl.h"
+
+namespace offline_pages {
+
+class PrefetchServiceImpl : public PrefetchService {
+ public:
+  PrefetchServiceImpl();
+  ~PrefetchServiceImpl() override;
+
+  // PrefetchService implementation:
+  void AddCandidatePrefetchURLs(
+      const std::vector<PrefetchURL>& suggested_urls) override;
+  void RemoveAllUnprocessedPrefetchURLs(const std::string& name_space) override;
+  void RemovePrefetchURLsByClientId(const ClientId& client_id) override;
+
+  // KeyedService implementation:
+  void Shutdown() override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(PrefetchServiceImpl);
+};
+
+}  // namespace offline_pages
+
+#endif  // COMPONENTS_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_SERVICE_IMPL_H_