Add per-section clearing and dismissed suggestions to snippets-internals

components/ntp_snippets/content_suggestions_provider.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_PROVIDER_H_
 #define COMPONENTS_NTP_SNIPPETS_CONTENT_SUGGESTIONS_PROVIDER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 72 matching lines @@
   // removal of the dismissed suggestion is the only change.
   virtual void DismissSuggestion(const std::string& suggestion_id) = 0;
 
   // Fetches the image for the suggestion with the given ID and returns it
   // through the callback. This fetch may occur locally or from the internet.
   // If that suggestion doesn't exist, doesn't have an image or if the fetch
   // fails, the callback gets a null image.
   virtual void FetchSuggestionImage(const std::string& suggestion_id,
                                     const ImageFetchedCallback& callback) = 0;
 
-  // Used only for debugging purposes. Clears all caches so that the next
-  // fetch starts from scratch.
-  virtual void ClearCachedSuggestionsForDebugging() = 0;
+  // Used only for debugging purposes. Clears all caches for the given category,
+  // so that the next fetch starts from scratch.
+  virtual void ClearCachedSuggestionsForDebugging(Category category) = 0;
+
+  // Used only for debugging purposes. Retrieves suggestions for the given
+  // |category| that have previously been dismissed and are still stored in the
+  // provider. If the provider doesn't store dismissed suggestions for the given
+  // |category|, it always returns an empty vector.
+  virtual std::vector<ContentSuggestion> GetDismissedSuggestionsForDebugging(
+      Category category) = 0;
 
   // Used only for debugging purposes. Clears the cache of dismissed
-  // suggestions, if present, so that no suggestions are suppressed. This does
-  // not necessarily make previously dismissed suggestions reappear, as they may
-  // have been permanently deleted, depending on the provider implementation.
-  virtual void ClearDismissedSuggestionsForDebugging() = 0;
+  // suggestions for the given |category|, if present, so that no suggestions
+  // are suppressed. This does not necessarily make previously dismissed
+  // suggestions reappear, as they may have been permanently deleted, depending
+  // on the provider implementation.
+  virtual void ClearDismissedSuggestionsForDebugging(Category category) = 0;
 
  protected:
   ContentSuggestionsProvider(Observer* observer,
                              CategoryFactory* category_factory);
 
   // Creates a unique ID. The given |within_category_id| must be unique among
   // all suggestion IDs from this provider for the given |category|. This method
   // combines it with the |category| to form an ID that is unique
   // application-wide, because this provider is the only one that provides
   // suggestions for that category.
   std::string MakeUniqueID(Category category,
                            const std::string& within_category_id);
 
   // Reverse functions for MakeUniqueID()
   Category GetCategoryFromUniqueID(const std::string& unique_id);
   std::string GetWithinCategoryIDFromUniqueID(const std::string& unique_id);
 
   Observer* observer() const { return observer_; }
   CategoryFactory* category_factory() const { return category_factory_; }
 
  private:
   Observer* observer_;
   CategoryFactory* category_factory_;
 };
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_CONTENT_SUGGESTIONS_PROVIDER_H_