[NTP::SectionOrder] Replace CategoryFactory with a category ranker.

components/ntp_snippets/content_suggestions_provider.h

Index: components/ntp_snippets/content_suggestions_provider.h
diff --git a/components/ntp_snippets/content_suggestions_provider.h b/components/ntp_snippets/content_suggestions_provider.h
index 8d941943475b434a3da0a0d90691e2cd097b4d4a..bdf16229695b8bf3aa18be9f754532ea69590df0 100644
--- a/components/ntp_snippets/content_suggestions_provider.h
+++ b/components/ntp_snippets/content_suggestions_provider.h
@@ -142,15 +142,11 @@ class ContentSuggestionsProvider {
   virtual void ClearDismissedSuggestionsForDebugging(Category category) = 0;
 
  protected:
-  ContentSuggestionsProvider(Observer* observer,
-                             CategoryFactory* category_factory);
+  ContentSuggestionsProvider(Observer* observer);
 
   Observer* observer() const { return observer_; }
-  CategoryFactory* category_factory() const { return category_factory_; }
-
  private:
   Observer* observer_;
-  CategoryFactory* category_factory_;
 };
 
 }  // namespace ntp_snippets