[NTP::SectionOrder] Enable ClickBased ranker by default.

components/ntp_snippets/features.cc

Index: components/ntp_snippets/features.cc
diff --git a/components/ntp_snippets/features.cc b/components/ntp_snippets/features.cc
index ed013a00d6d2c3f18ad961c21477eb6aa0cb1b71..59c54b29d559c872771ba77079fa8af93c1728e2 100644
--- a/components/ntp_snippets/features.cc
+++ b/components/ntp_snippets/features.cc
@@ -61,7 +61,7 @@ CategoryRankerChoice GetSelectedCategoryRanker() {
 
   if (category_ranker_value.empty()) {
     // Default, Enabled or Disabled.
-    return CategoryRankerChoice::CONSTANT;
+    return CategoryRankerChoice::CLICK_BASED;
   }
   if (category_ranker_value == kCategoryRankerConstantRanker) {
     return CategoryRankerChoice::CONSTANT;