[NTP::SectionOrder] First version of click based category ranker.

components/ntp_snippets/pref_names.cc

Index: components/ntp_snippets/pref_names.cc
diff --git a/components/ntp_snippets/pref_names.cc b/components/ntp_snippets/pref_names.cc
index fbf55054eb6fbf76595fdb6b09d5aca64af50043..dced63df980be7996c9402970d2ddee6ed2dc1a5 100644
--- a/components/ntp_snippets/pref_names.cc
+++ b/components/ntp_snippets/pref_names.cc
@@ -61,5 +61,8 @@ const char kUserClassifierLastTimeToShowSuggestions[] =
 const char kUserClassifierLastTimeToUseSuggestions[] =
     "ntp_suggestions.user_classifier.last_time_to_use_suggestions";
 
+const char kClickBasedCategoryRankerOrderWithClicks[] =
+    "ntp_suggestions.click_based_category_ranker.category_order_with_clicks";
+
 }  // namespace prefs
 }  // namespace ntp_snippets