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

components/ntp_snippets/category_rankers/category_ranker.h

Index: components/ntp_snippets/category_rankers/category_ranker.h
diff --git a/components/ntp_snippets/category_rankers/category_ranker.h b/components/ntp_snippets/category_rankers/category_ranker.h
index 30cf36bf8e2670e0166fa079f0bf66f59d583c09..c403625e6166625b8c597ef51bbb087a45a000a6 100644
--- a/components/ntp_snippets/category_rankers/category_ranker.h
+++ b/components/ntp_snippets/category_rankers/category_ranker.h
@@ -36,6 +36,9 @@ class CategoryRanker {
 
   // Called whenever a suggestion is opened by the user.
   virtual void OnSuggestionOpened(Category category) = 0;
+
+  // Called whenever a category is dismissed by the user.
+  virtual void OnCategoryDismissed(Category category) = 0;
 };
 
 }  // namespace ntp_snippets