Reconcile the request queue on startup.

components/offline_pages/core/background/reconcile_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_CORE_BACKGROUND_RECONCILE_TASK_H_
+#define COMPONENTS_OFFLINE_PAGES_CORE_BACKGROUND_RECONCILE_TASK_H_
+
+#include <memory>
+#include <vector>
+
+#include "base/memory/weak_ptr.h"
+#include "components/offline_pages/core/background/request_queue_store.h"
+#include "components/offline_pages/core/background/save_page_request.h"
+#include "components/offline_pages/core/task.h"
+
+namespace offline_pages {
+
+// The reconcile task should be run at request coordinator startup to find any
+// tasks that were offlining when chrome died, and change the state back to
+// available.
+class ReconcileTask : public Task {
+ public:
+  ReconcileTask(RequestQueueStore* store,
+                const RequestQueueStore::UpdateCallback& callback);
+  ~ReconcileTask() override;
+
+  // TaskQueue::Task implementation:
+  // Starts the async chain.
+  void Run() override;
+
+ private:
+  // Step 1. Get results from the store.
+  void GetRequests();
+
+  // Step 2. Flip OFFLINING requests to AVAILABLE and put back in queue.
+  void Reconcile(bool success,
+                 std::vector<std::unique_ptr<SavePageRequest>> requests);
+
+  // Step 3. Processes update result.
+  void UpdateCompleted(std::unique_ptr<UpdateRequestsResult> update_result);
+
+  // Member variables, all pointers are not owned here.
+  RequestQueueStore* store_;
+  // Callback to complete the task.
+  RequestQueueStore::UpdateCallback callback_;
+  // Allows us to pass a weak pointer to callbacks.
+  base::WeakPtrFactory<ReconcileTask> weak_ptr_factory_;
+};
+
+}  // namespace offline_pages
+
+#endif  // COMPONENTS_OFFLINE_PAGES_CORE_BACKGROUND_RECONCILE_TASK_H_