[Offline pages] Applying StoreState to track RequestQueueStore state

components/offline_pages/background/request_queue_in_memory_store.h

Index: components/offline_pages/background/request_queue_in_memory_store.h
diff --git a/components/offline_pages/background/request_queue_in_memory_store.h b/components/offline_pages/background/request_queue_in_memory_store.h
index 364de0b1f24fa16c0d246f0746c8789116d020f3..ff6fecd0e393bfd80314708ea4babbcde269dc7c 100644
--- a/components/offline_pages/background/request_queue_in_memory_store.h
+++ b/components/offline_pages/background/request_queue_in_memory_store.h
@@ -42,6 +42,7 @@ class RequestQueueInMemoryStore : public RequestQueueStore {
       const UpdateMultipleRequestsCallback& callback) override;
 
   void Reset(const ResetCallback& callback) override;
+  StoreState state() const override;
 
  private:
   typedef std::map<int64_t, SavePageRequest> RequestsMap;