Make ContentSuggestionsService recognize new/removed categories

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 <string>
 #include <vector>
@@ skipping 108 matching lines @@
  private:
   friend class ContentSuggestionsServiceTest;
 
   // This is just an arbitrary ordering by ID, used by the maps in this class,
   // because the ordering needs to be constant for maps.
   struct CompareCategoriesByID {
     bool operator()(const Category& left, const Category& right) const;
   };
 
   // Implementation of ContentSuggestionsProvider::Observer.
-  void OnNewSuggestions(Category changed_category,
+  void OnNewSuggestions(ContentSuggestionsProvider* provider,
+                        Category category,
                         std::vector<ContentSuggestion> suggestions) override;
-  void OnCategoryStatusChanged(Category changed_category,
+  void OnCategoryStatusChanged(ContentSuggestionsProvider* provider,
+                               Category category,
                                CategoryStatus new_status) override;
   void OnProviderShutdown(ContentSuggestionsProvider* provider) override;
 
-  // Checks whether a provider for the given |category| is registered.
-  bool IsCategoryRegistered(Category category) const;
+  // Registers the given |provider| for the given |category|, unless it is
+  // already registered. Returns true if the category was newly registered or
+  // false if it was present before.
+  bool RegisterCategoryIfRequired(ContentSuggestionsProvider* provider,
+                                  Category category);
 
   // Fires the OnCategoryStatusChanged event for the given |category|.
   void NotifyCategoryStatusChanged(Category category);
 
   // Whether the content suggestions feature is enabled.
   State state_;
 
   // Provides new and existing categories and an order for them.
   CategoryFactory category_factory_;
 
   // All registered providers. A provider may be contained multiple times, if it
   // provides multiple categories. The keys of this map are exactly the entries
   // of |categories_|.
   std::map<Category, ContentSuggestionsProvider*, CompareCategoriesByID>
-      providers_;
+      providers_by_category_;
 
   // All current suggestion categories, in an order determined by the
   // |category_factory_|. This vector contains exactly the same categories as
   // |providers_|.
   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>, CompareCategoriesByID>
       suggestions_by_category_;
 
   // Map used to determine the category of a suggestion (of which only the ID
   // is available). This also determines the provider that delivered the
   // suggestion.
   std::map<std::string, Category> id_category_map_;
 
   base::ObserverList<Observer> observers_;
 
   const std::vector<ContentSuggestion> no_suggestions_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentSuggestionsService);
 };
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_CONTENT_SUGGESTIONS_SERVICE_H_