Add an API to Pause and Resume background offlining requests.

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>
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "components/offline_pages/background/save_page_request.h"
 #include "components/offline_pages/offline_page_item.h"
 
 namespace offline_pages {
 
 class RequestQueueStore;
 class SavePageRequest;

[fgorski, 2016/08/10 16:00:09]

please remove now that you are adding the .h file.

[Pete Williamson, 2016/08/10 21:38:00]

Done.

 
 // Class responsible for managing save page requests.
 class RequestQueue {
  public:
   enum class GetRequestsResult {
     SUCCESS,
     STORE_FAILURE,
   };
 
   enum class AddRequestResult {
@@ skipping 43 matching lines @@
 
   // Removes the request matching the |request_id|. Result is returned through
   // |callback|.
   void RemoveRequest(int64_t request_id, const UpdateRequestCallback& callback);
 
   // Removes the requests matching the |client_ids|. Results are returned
   // through |callback|.
   void RemoveRequestsByClientId(const std::vector<ClientId>& client_id,
                                 const UpdateRequestCallback& 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,

[fgorski, 2016/08/10 16:00:09]

Is the plan to add one of these for everything that we are going to be changing?
What other options did you consider, before we settle on this?

I see Dmitry made a similar comment on this patch before. Can we discuss this in
the office?

[Pete Williamson, 2016/08/10 21:38:00]

Sure, let's discuss this.  Leaving code as is for now, I'll change if we decide
to after our discussion.

[Pete Williamson, 2016/08/10 23:34:40]

After discussion, plan is to start updating the entire request instead of
individual fields of the item, so added a TODO here to change to the new way.

+                           const SavePageRequest::RequestState new_state,
+                           const UpdateRequestCallback& callback);
+
   void GetForUpdateDone(
       const RequestQueue::UpdateRequestCallback& update_callback,
       const SavePageRequest& update_request,
       bool success,
       const std::vector<SavePageRequest>& requests);
 
  private:
   // Callback used by |PurgeRequests|.
   typedef base::Callback<void(UpdateRequestResult,
                               int /* removed requests count */)>
       PurgeRequestsCallback;
 
   // Purges the queue, removing the requests that are no longer relevant, e.g.
   // expired request. Result is returned through |callback| carries the number
   // of removed requests.
   void PurgeRequests(const PurgeRequestsCallback& callback);
 
   std::unique_ptr<RequestQueueStore> store_;
 
   // 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_