[NTP::SectionOrder] Propagate new order through ContentSuggestionsService.

components/ntp_snippets/content_suggestions_service.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_NTP_SNIPPETS_CONTENT_SUGGESTIONS_SERVICE_H_
 #define COMPONENTS_NTP_SNIPPETS_CONTENT_SUGGESTIONS_SERVICE_H_
 
 #include <map>
 #include <memory>
 #include <set>
@@ skipping 82 matching lines @@
                             std::unique_ptr<CategoryRanker> category_ranker);
   ~ContentSuggestionsService() override;
 
   // Inherited from KeyedService.
   void Shutdown() override;
 
   static void RegisterProfilePrefs(PrefRegistrySimple* registry);
 
   State state() { return state_; }
 
-  // Gets all categories for which a provider is registered. The categories
-  // may or may not be available, see |GetCategoryStatus()|.
-  const std::vector<Category>& GetCategories() const { return categories_; }
+  // Gets all categories for which a provider is registered. The categories may
+  // or may not be available, see |GetCategoryStatus()|. The order in which the
+  // categories are returned is the order in which they should be displayed.
+  std::vector<Category> GetCategories() const;
 
   // Gets the status of a category.
   CategoryStatus GetCategoryStatus(Category category) const;
 
   // Gets the meta information of a category.
   base::Optional<CategoryInfo> GetCategoryInfo(Category category) const;
 
   // Gets the available suggestions for a category. The result is empty if the
   // category is available and empty, but also if the category is unavailable
   // for any reason, see |GetCategoryStatus()|.
@@ skipping 133 matching lines @@
 
   // Removes a suggestion from the local store |suggestions_by_category_|, if it
   // exists. Returns true if a suggestion was removed.
   bool RemoveSuggestionByID(const ContentSuggestion::ID& suggestion_id);
 
   // Fires the OnCategoryStatusChanged event for the given |category|.
   void NotifyCategoryStatusChanged(Category category);
 
   void OnSignInStateChanged();
 
-  void SortCategories();
-
   // Re-enables a dismissed category, making querying its provider possible.
   void RestoreDismissedCategory(Category category);
 
   void RestoreDismissedCategoriesFromPrefs();
   void StoreDismissedCategoriesToPrefs();
 
   // Whether the content suggestions feature is enabled.
   State state_;
 
   // All registered providers, owned by the service.
   std::vector<std::unique_ptr<ContentSuggestionsProvider>> providers_;
 
   // All registered categories and their providers. A provider may be contained
   // multiple times, if it provides multiple categories. The keys of this map
   // are exactly the entries of |categories_| and the values are a subset of
   // |providers_|.
   std::map<Category, ContentSuggestionsProvider*, Category::CompareByID>
       providers_by_category_;
 
   // All dismissed categories and their providers. These may be restored by
   // RestoreDismissedCategories(). The provider can be null if the dismissed
   // category has received no updates since initialisation.
   // (see RestoreDismissedCategoriesFromPrefs())
   std::map<Category, ContentSuggestionsProvider*, Category::CompareByID>
       dismissed_providers_by_category_;
 
-  // All current suggestion categories, in an order determined by the
-  // |category_factory_|. This vector contains exactly the same categories as
-  // |providers_by_category_|.
+  // All current suggestion categories in arbitrary order. This vector contains
+  // exactly the same categories as |providers_by_category_|.
   std::vector<Category> categories_;
 
   // All current suggestions grouped by category. This contains an entry for
   // every category in |categories_| whose status is an available status. It may
   // contain an empty vector if the category is available but empty (or still
   // loading).
   std::map<Category, std::vector<ContentSuggestion>, Category::CompareByID>
       suggestions_by_category_;
 
   // Observer for the SigninManager. All observers are notified when the signin
@@ skipping 22 matching lines @@
 
   // Provides order for categories.
   std::unique_ptr<CategoryRanker> category_ranker_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentSuggestionsService);
 };
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_CONTENT_SUGGESTIONS_SERVICE_H_