[Offline pages] Adding GetRequestsTask to RequestQueue

components/offline_pages/background/get_requests_task.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_BACKGROUND_GET_REQUESTS_TASK_H_
+#define COMPONENTS_OFFLINE_PAGES_BACKGROUND_GET_REQUESTS_TASK_H_
+
+#include <memory>
+#include <vector>
+
+#include "base/memory/weak_ptr.h"
+#include "components/offline_pages/background/request_queue_store.h"
+#include "components/offline_pages/core/task.h"
+
+namespace offline_pages {
+
+class GetRequestsTask : public Task {
+ public:
+  GetRequestsTask(RequestQueueStore* store,
+                  const RequestQueueStore::GetRequestsCallback& callback);
+  ~GetRequestsTask() override;
+
+  // Task implementation:
+  void Run() override;
+
+ private:
+  // Step 1: Read the requests from he store.
+  void ReadRequest();
+  // Step 2: Calls the callback with result, completes the task.
+  void CompleteWithResult(
+      bool success,
+      std::vector<std::unique_ptr<SavePageRequest>> requests);
+
+  // Store from which requests will be read.
+  RequestQueueStore* store_;
+  // Callback used to return the read results.
+  RequestQueueStore::GetRequestsCallback callback_;
+
+  base::WeakPtrFactory<GetRequestsTask> weak_ptr_factory_;
+  DISALLOW_COPY_AND_ASSIGN(GetRequestsTask);
+};
+
+}  // namespace offline_pages
+
+#endif  // COMPONENTS_OFFLINE_PAGES_BACKGROUND_GET_REQUESTS_TASK_H_