PERF: Don't calculate the same query twice.

app/models/site_setting.rb

@@ -99,8 +99,8 @@ class SiteSetting < ActiveRecord::Base
   end
 
   def self.min_redirected_to_top_period(duration)
-    period = ListController.best_period_for(duration)
-    return period if TopTopic.topics_per_period(period) >= SiteSetting.topics_per_period_in_top_page
+    period = ListController.best_period_with_topics_for(duration)
+    return period if period
 
     # not enough topics
     nil

app/models/top_topic.rb

@@ -4,12 +4,6 @@ class TopTopic < ActiveRecord::Base
 
   belongs_to :topic
 
-  def self.topics_per_period(period)
-    DistributedMemoizer.memoize("#{Discourse.current_hostname}_topics_per_period_#{period}", 1.day) do
-      TopTopic.where("#{period}_score > 0").count
-    end.to_i
-  end
-
   # The top topics we want to refresh often
   def self.refresh_daily!
     transaction do