[NTP Snippets] NTPSnippetsService: notify about new suggestions only in changed categories

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 253 matching lines @@
   // Enables the service. Do not call directly, use |EnterState| instead.
   void EnterStateReady();
 
   // Disables the service. Do not call directly, use |EnterState| instead.
   void EnterStateDisabled();
 
   // Disables the service permanently because an unrecoverable error occurred.
   // Do not call directly, use |EnterState| instead.
   void EnterStateError();
 
-  // Converts the cached snippets to article content suggestions and notifies
-  // the observers.
-  void NotifyNewSuggestions();
+  // Converts the cached snippets in the given |category| to content suggestions
+  // and notifies the observer.
+  void NotifyNewSuggestions(Category category);
 
   // 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();
 
@@ skipping 72 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_