[NTP::SectionOrder] Make ClickBasedRanker move dismissed sections down.

components/ntp_snippets/category_rankers/click_based_category_ranker.h

Index: components/ntp_snippets/category_rankers/click_based_category_ranker.h
diff --git a/components/ntp_snippets/category_rankers/click_based_category_ranker.h b/components/ntp_snippets/category_rankers/click_based_category_ranker.h
index 4b3a8a20f5fea117da0d0b8fe158c74f5f4df477..698940d737ea91ced36525e07ad1a8d927c07619 100644
--- a/components/ntp_snippets/category_rankers/click_based_category_ranker.h
+++ b/components/ntp_snippets/category_rankers/click_based_category_ranker.h
@@ -33,6 +33,7 @@ class ClickBasedCategoryRanker : public CategoryRanker {
   void ClearHistory(base::Time begin, base::Time end) override;
   void AppendCategoryIfNecessary(Category category) override;
   void OnSuggestionOpened(Category category) override;
+  void OnCategoryDismissed(Category category) override;
 
   static void RegisterProfilePrefs(PrefRegistrySimple* registry);
 
@@ -44,6 +45,10 @@ class ClickBasedCategoryRanker : public CategoryRanker {
   // passing margin). For testing only.
   static int GetNumTopCategoriesWithExtraMargin();
 
+  // Returns number of positions by which a dismissed category is downgraded.
+  // For testing only.
+  static int GetDismissedCategoryPenalty();
+
  private:
   struct RankedCategory {
     Category category;