[NTP Snippets] Persist remote categories in prefs

components/ntp_snippets/remote/ntp_snippets_service.h

 // Copyright 2015 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_NTP_SNIPPETS_REMOTE_NTP_SNIPPETS_SERVICE_H_
 #define COMPONENTS_NTP_SNIPPETS_REMOTE_NTP_SNIPPETS_SERVICE_H_
 
 #include <cstddef>
 #include <map>
 #include <memory>
@@ skipping 261 matching lines @@
   // Converts the cached snippets to article content suggestions and notifies
   // the observers.
   void NotifyNewSuggestions();
 
   // Updates the internal status for |category| to |category_status_| and
   // notifies the content suggestions observer if it changed.
   void UpdateCategoryStatus(Category category, CategoryStatus status);
   // Calls UpdateCategoryStatus() for all provided categories.
   void UpdateAllCategoryStatus(CategoryStatus status);
 
+  void RestoreCategoriesFromPrefs();
+  void StoreCategoriesToPrefs();
+
   State state_;
 
   PrefService* pref_service_;
 
   const Category articles_category_;
 
   // TODO(sfiera): Reduce duplication of CategoryContent with CategoryInfo.
   struct CategoryContent {
     CategoryStatus status = CategoryStatus::INITIALIZING;
 
@@ skipping 61 matching lines @@
 
   // Request throttler for limiting requests to thumbnail images.
   RequestThrottler thumbnail_requests_throttler_;
 
   DISALLOW_COPY_AND_ASSIGN(NTPSnippetsService);
 };
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_REMOTE_NTP_SNIPPETS_SERVICE_H_