Adds an observer for the request coordinator.

components/offline_pages/background/request_queue_store.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_STORE_H_
 #define COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_QUEUE_STORE_H_
 
 #include <stdint.h>
 #include <vector>
 
 #include "base/callback.h"
 #include "components/offline_pages/background/request_queue.h"
 #include "components/offline_pages/background/save_page_request.h"
 #include "components/offline_pages/offline_page_item.h"
 
 namespace offline_pages {
 
 // Interface for classes storing save page requests.
 class RequestQueueStore {
  public:
   enum class UpdateStatus {
     ADDED,    // Request was added successfully.
     UPDATED,  // Request was updated successfully.
     FAILED,   // Add or update attempt failed.
   };
-  // TODO(petewil): What if no items were updated?  Maybe this should work more
-  // like DeleteCallback, passing pairs of request_id and status.
 
   typedef base::Callback<void(
       bool /* success */,
       const std::vector<SavePageRequest>& /* requests */)>
       GetRequestsCallback;
   typedef base::Callback<void(UpdateStatus)> UpdateCallback;
+  // TODO(petewil) - UpdateMultiple looks exactly like Remove, consider
+  // merging them into a single callback.
   typedef base::Callback<void(
-      const RequestQueue::UpdateMultipleRequestResults&)>
+      const RequestQueue::UpdateMultipleRequestResults& /* statuses*/,
+      const std::vector<SavePageRequest>& /* requests */)>
+      UpdateMultipleRequestsCallback;
+  typedef base::Callback<void(
+      const RequestQueue::UpdateMultipleRequestResults& /* statuses */,
+      const std::vector<SavePageRequest>& /* requests */)>
       RemoveCallback;
   typedef base::Callback<void(bool /* success */)> ResetCallback;
 
   virtual ~RequestQueueStore(){};
 
   // Gets all of the requests from the store.
   virtual void GetRequests(const GetRequestsCallback& callback) = 0;
 
   // Asynchronously adds or updates request in store.
   // Result of the update is passed in the callback.
   virtual void AddOrUpdateRequest(const SavePageRequest& request,
                                   const UpdateCallback& callback) = 0;
 
   // Asynchronously removes requests from the store using their IDs.
   // Result of the update, and a number of removed pages is passed in the
   // callback.
   // Result of remove should be false, when one of the provided items couldn't
   // be deleted, e.g. because it was missing.
   virtual void RemoveRequests(const std::vector<int64_t>& request_ids,
                               const RemoveCallback& callback) = 0;
 
   // Asynchronously changes the state of requests from the store using their
   // request id.
   virtual void ChangeRequestsState(
       const std::vector<int64_t>& request_ids,
       const SavePageRequest::RequestState new_state,
-      const UpdateCallback& callback) = 0;
+      const UpdateMultipleRequestsCallback& callback) = 0;
 
   // Resets the store.
   virtual void Reset(const ResetCallback& callback) = 0;
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_QUEUE_STORE_H_