Support server categories in NTPSnippetsService.

components/ntp_snippets/ntp_snippets_service.h

Index: components/ntp_snippets/ntp_snippets_service.h
diff --git a/components/ntp_snippets/ntp_snippets_service.h b/components/ntp_snippets/ntp_snippets_service.h
index 555e0924e504475301a3f676a74790620d72e46d..cfb0b21c7644792a64ae20f5cb8b177b581b096c 100644
--- a/components/ntp_snippets/ntp_snippets_service.h
+++ b/components/ntp_snippets/ntp_snippets_service.h
@@ -153,8 +153,8 @@ class NTPSnippetsService : public ContentSuggestionsProvider,
   static int GetMaxSnippetCountForTesting();
 
   // Available snippets, only for unit tests.
-  const NTPSnippet::PtrVector& GetSnippetsForTesting() const {
-    return snippets_;
+  const NTPSnippet::PtrVector& GetSnippetsForTesting(Category category) const {
+    return categories_.find(category)->second.snippets;
   }
 
  private:
@@ -222,7 +222,7 @@ class NTPSnippetsService : public ContentSuggestionsProvider,
   void OnFetchFinished(NTPSnippetsFetcher::OptionalSnippets snippets);
 
   // Merges newly available snippets with the previously available list.
-  void MergeSnippets(NTPSnippet::PtrVector new_snippets);
+  void MergeSnippets(Category category, NTPSnippet::PtrVector new_snippets);
 
   std::set<std::string> GetSnippetHostsFromPrefs() const;
   void StoreSnippetHostsToPrefs(const std::set<std::string>& hosts);
@@ -239,14 +239,14 @@ class NTPSnippetsService : public ContentSuggestionsProvider,
   void FinishInitialization();
 
   void OnSnippetImageFetchedFromDatabase(const ImageFetchedCallback& callback,
-                                         const std::string& snippet_id,
+                                         const std::string& suggestion_id,

[Marc Treib, 2016/08/25 09:10:50]

snippet_id, also below and in the .cc

[sfiera, 2016/08/25 12:45:13]

|suggestion_id| is correct, I think. Nowhere do we pass |suggestion_id| to the
database; we extract a snippet ID for the database and bind the suggestion_id
(which is what we need in this class) to callbacks.

[Marc Treib, 2016/08/25 12:56:24]

Ah, you're right. In fact, ...

                                          std::string data);
 
   void OnSnippetImageDecodedFromDatabase(const ImageFetchedCallback& callback,
-                                         const std::string& snippet_id,
+                                         const std::string& suggestion_id,
                                          const gfx::Image& image);
 
-  void FetchSnippetImageFromNetwork(const std::string& snippet_id,
+  void FetchSnippetImageFromNetwork(const std::string& suggestion_id,
                                     const ImageFetchedCallback& callback);
 
   void OnSnippetImageDecodedFromNetwork(const ImageFetchedCallback& callback,
@@ -261,7 +261,7 @@ class NTPSnippetsService : public ContentSuggestionsProvider,
   // Verifies state transitions (see |State|'s documentation) and applies them.
   // Also updates the provider status. Does nothing except updating the provider
   // status if called with the current state.
-  void EnterState(State state, CategoryStatus status);
+  void EnterState(State state);
 
   // Enables the service and triggers a fetch if required. Do not call directly,
   // use |EnterState| instead.
@@ -278,24 +278,37 @@ class NTPSnippetsService : public ContentSuggestionsProvider,
   // the observers.
   void NotifyNewSuggestions();
 
-  // Updates the internal status |category_status_| and notifies the content
-  // suggestions observer if it changed.
-  void UpdateCategoryStatus(CategoryStatus status);
+  // 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);
 
   State state_;
 
-  CategoryStatus category_status_;
-
   PrefService* pref_service_;
 
   suggestions::SuggestionsService* suggestions_service_;
 
-  // All current suggestions (i.e. not dismissed ones).
-  NTPSnippet::PtrVector snippets_;
+  const Category articles_category_;
 
-  // Suggestions that the user dismissed. We keep these around until they expire
-  // so we won't re-add them on the next fetch.
-  NTPSnippet::PtrVector dismissed_snippets_;
+  struct CategoryContent {
+    CategoryStatus status = CategoryStatus::INITIALIZING;
+
+    // True iff the server returned results in this category in the last fetch.
+    // We never remove categories that the server still provides, but if the
+    // server stops providing a category, we won't yet report it as NOT_PROVIDED
+    // while we still have non-expired snippets in it.
+    bool provided_by_server = true;
+
+    // All current suggestions (i.e. not dismissed ones).
+    NTPSnippet::PtrVector snippets;
+
+    // Suggestions that the user dismissed. We keep these around until they
+    // expire so we won't re-add them on the next fetch.
+    NTPSnippet::PtrVector dismissed;
+  };
+  std::map<Category, CategoryContent, Category::CompareByID> categories_;
 
   // The ISO 639-1 code of the language used by the application.
   const std::string application_language_code_;
@@ -338,8 +351,6 @@ class NTPSnippetsService : public ContentSuggestionsProvider,
   // loaded. The nuke will be executed after the database load finishes.
   bool nuke_after_load_;
 
-  const Category provided_category_;
-
   // Request throttler for limiting requests to thumbnail images.
   RequestThrottler thumbnail_requests_throttler_;