[Offline pages] Introduction of MarkAttemptStartedTask with tests

components/offline_pages/background/mark_attempt_started_task.cc

+// 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.
+
+#include "components/offline_pages/background/mark_attempt_started_task.h"
+
+#include <vector>
+
+#include "base/bind.h"
+#include "base/time/time.h"
+
+namespace offline_pages {
+
+MarkAttemptStartedTask::MarkAttemptStartedTask(
+    RequestQueueStore* store,
+    int64_t request_id,
+    const RequestQueueStore::UpdateCallback& callback)
+    : store_(store),
+      request_id_(request_id),
+      callback_(callback),
+      weak_ptr_factory_(this) {}
+
+MarkAttemptStartedTask::~MarkAttemptStartedTask() {}
+
+void MarkAttemptStartedTask::Run() {
+  ReadRequest();
+}
+
+void MarkAttemptStartedTask::ReadRequest() {
+  std::vector<int64_t> request_ids{request_id_};
+  store_->GetRequestsByIds(
+      request_ids, base::Bind(&MarkAttemptStartedTask::MarkAttemptStarted,
+                              weak_ptr_factory_.GetWeakPtr()));
+}
+
+void MarkAttemptStartedTask::MarkAttemptStarted(
+    std::unique_ptr<UpdateRequestsResult> read_result) {
+  if (read_result->store_state != StoreState::LOADED ||
+      read_result->item_statuses.front().second != ItemActionStatus::SUCCESS ||
+      read_result->updated_items.size() != 1) {
+    CompleteWithResult(std::move(read_result));
+    return;
+  }
+
+  // It is perfectly fine to reuse the read_result->updated_items collection, as
+  // it is owned by this callback and will be destroyed when out of scope.
+  read_result->updated_items[0].MarkAttemptStarted(base::Time::Now());
+  store_->UpdateRequests(read_result->updated_items,
+                         base::Bind(&MarkAttemptStartedTask::CompleteWithResult,
+                                    weak_ptr_factory_.GetWeakPtr()));
+}
+
+void MarkAttemptStartedTask::CompleteWithResult(
+    std::unique_ptr<UpdateRequestsResult> result) {
+  callback_.Run(std::move(result));
+  TaskComplete();
+}
+
+}  // namespace offline_pages