[Offline pages] Applying StoreState to track RequestQueueStore state

components/offline_pages/background/request_queue_in_memory_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_IN_MEMORY_STORE_H_
 #define COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_QUEUE_IN_MEMORY_STORE_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 24 matching lines @@
                       const RemoveCallback& callback) override;
 
   // Set the state of associated requests to |new_state|.  The callback will get
   // a list of UpdateMultipleRequestResults, and a list of the updated requests.
   void ChangeRequestsState(
       const std::vector<int64_t>& request_ids,
       const SavePageRequest::RequestState new_state,
       const UpdateMultipleRequestsCallback& callback) override;
 
   void Reset(const ResetCallback& callback) override;
+  StoreState state() const override;
 
  private:
   typedef std::map<int64_t, SavePageRequest> RequestsMap;
   RequestsMap requests_;
 
   DISALLOW_COPY_AND_ASSIGN(RequestQueueInMemoryStore);
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_QUEUE_IN_MEMORY_STORE_H_