Only show Last N Pages in the UI when the corresponding tab is visible.

components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.h

Index: components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.h
diff --git a/components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.h b/components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.h
index 6a4e71dc31e17b29149839041612261adf501e1d..249bf9146d688a5a450f0ba268b448fb2422bbe2 100644
--- a/components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.h
+++ b/components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.h
@@ -17,6 +17,8 @@
 #include "components/ntp_snippets/category_status.h"
 #include "components/ntp_snippets/content_suggestion.h"
 #include "components/ntp_snippets/content_suggestions_provider.h"
+#include "components/offline_pages/core/downloads/download_ui_adapter.h"
+#include "components/offline_pages/core/downloads/download_ui_item.h"
 #include "components/offline_pages/core/offline_page_model.h"
 
 class PrefRegistrySimple;
@@ -27,11 +29,12 @@ namespace ntp_snippets {
 // Provides recent tabs content suggestions from the offline pages model.
 class RecentTabSuggestionsProvider
     : public ContentSuggestionsProvider,
-      public offline_pages::OfflinePageModel::Observer {
+      public offline_pages::DownloadUIAdapter::Observer {
  public:
   RecentTabSuggestionsProvider(
       ContentSuggestionsProvider::Observer* observer,
       offline_pages::OfflinePageModel* offline_page_model,
+      offline_pages::RequestCoordinator* request_coordinator,
       PrefService* pref_service);
   ~RecentTabSuggestionsProvider() override;
 
@@ -59,17 +62,11 @@ class RecentTabSuggestionsProvider
  private:
   friend class RecentTabSuggestionsProviderTest;
 
-  void GetPagesMatchingQueryCallbackForGetDismissedSuggestions(
-      const DismissedSuggestionsCallback& callback,
-      const std::vector<offline_pages::OfflinePageItem>& offline_pages) const;
-
-  // OfflinePageModel::Observer implementation.
-  void OfflinePageModelLoaded(offline_pages::OfflinePageModel* model) override;
-  void OfflinePageAdded(
-      offline_pages::OfflinePageModel* model,
-      const offline_pages::OfflinePageItem& added_page) override;
-  void OfflinePageDeleted(int64_t offline_id,
-                          const offline_pages::ClientId& client_id) override;
+  // DownloadUIAdapter::Observer implementation.
+  void ItemsLoaded() override;
+  void ItemAdded(const offline_pages::DownloadUIItem& ui_item) override;
+  void ItemUpdated(const offline_pages::DownloadUIItem& ui_item) override;
+  void ItemDeleted(const std::string& ui_item_guid) override;
 
   void GetPagesMatchingQueryCallbackForFetchRecentTabs(
       const std::vector<offline_pages::OfflinePageItem>& offline_pages);
@@ -83,21 +80,20 @@ class RecentTabSuggestionsProvider
 
   // Converts an OfflinePageItem to a ContentSuggestion for the

[vitaliii, 2017/02/15 10:12:15]

s/OfflinePageItem/DownloadUIItem

[dewittj, 2017/02/15 19:49:45]

Done.

   // |provided_category_|.
-  ContentSuggestion ConvertOfflinePage(
-      const offline_pages::OfflinePageItem& offline_page) const;
+  ContentSuggestion ConvertUIItem(
+      const offline_pages::DownloadUIItem& ui_item) const;
 
   // Removes duplicates for the same URL leaving only the most recently created
   // items, returns at most |GetMaxSuggestionsCount()| ContentSuggestions
   // corresponding to the remaining items, sorted by creation time (newer
   // first).
   std::vector<ContentSuggestion> GetMostRecentlyCreatedWithoutDuplicates(
-      std::vector<const offline_pages::OfflinePageItem*> offline_page_items)
-      const;
+      std::vector<const offline_pages::DownloadUIItem*> ui_items) const;
 
   // Fires the |OnSuggestionInvalidated| event for the suggestion corresponding
   // to the given |offline_id| and deletes it from the dismissed IDs list, if
   // necessary.
-  void InvalidateSuggestion(int64_t offline_id);
+  void InvalidateSuggestion(const std::string& ui_item_guid);
 
   // Reads dismissed IDs from Prefs.
   std::set<std::string> ReadDismissedIDsFromPrefs() const;
@@ -107,7 +103,7 @@ class RecentTabSuggestionsProvider
 
   CategoryStatus category_status_;
   const Category provided_category_;
-  offline_pages::OfflinePageModel* offline_page_model_;
+  offline_pages::DownloadUIAdapter* recent_tabs_ui_adapter_;
 
   PrefService* pref_service_;