[Offline pages] Introduction of MarkAttemptStartedTask with tests

components/offline_pages/background/request_queue.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_REQUEST_QUEUE_H_
 #define COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_QUEUE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 77 matching lines @@
   // others.
   void RemoveRequests(const std::vector<int64_t>& request_ids,
                       const UpdateCallback& callback);
 
   // Changes the state to |new_state| for requests matching the
   // |request_ids|. Results are returned through |callback|.
   void ChangeRequestsState(const std::vector<int64_t>& request_ids,
                            const SavePageRequest::RequestState new_state,
                            const UpdateCallback& callback);
 
+  // Marks attempt with |request_id| as started. Results are returned through
+  // |callback|.
+  void MarkAttemptStarted(int64_t request_id, const UpdateCallback& callback);
+
   void GetForUpdateDone(
       const RequestQueue::UpdateRequestCallback& update_callback,
       const SavePageRequest& update_request,
       bool success,
       std::vector<std::unique_ptr<SavePageRequest>> requests);
 
  private:
   // Callback used by |PurgeRequests|.
   typedef base::Callback<void(UpdateRequestResult,
                               int /* removed requests count */)>
@@ skipping 11 matching lines @@
 
   // Allows us to pass a weak pointer to callbacks.
   base::WeakPtrFactory<RequestQueue> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RequestQueue);
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_QUEUE_H_