Show Private Messages pill as a topic list rather than individual messages.

lib/topic_query.rb

@@ -135,6 +135,17 @@ class TopicQuery
     end
   end
 
+  def list_private_messages(user)
+    list = private_messages_for(user)
+    TopicList.new(:private_messages, user, list)
+  end
+
+  def list_private_messages_sent(user)
+    list = private_messages_for(user)
+    list = list.where(user_id: user.id)
+    TopicList.new(:private_messages, user, list)
+  end
+
 
   def list_uncategorized
     create_list(:uncategorized, unordered: true) do |list|
@@ -190,6 +201,22 @@ class TopicQuery
       TopicList.new(filter, @user, topics)
     end
 
+    def private_messages_for(user)
+      options = @options
+      options.reverse_merge!(per_page: SiteSetting.topics_per_page)
+
+      # Start with a list of all topics
+      result = Topic.where(id: TopicAllowedUser.where(user_id: user.id).pluck(:topic_id))
+      result = result.joins("LEFT OUTER JOIN topic_users AS tu ON (topics.id = tu.topic_id AND tu.user_id = #{user.id.to_i})")
+      result = result.order(TopicQuery.order_nocategory_basic_bumped)
+      result = result.private_messages
+
+      result = result.limit(options[:per_page]) unless options[:limit] == false
+      result = result.visible if options[:visible] || @user.nil? || @user.regular?
+      result = result.offset(options[:page].to_i * options[:per_page]) if options[:page]
+      result
+    end
+
     # Create results based on a bunch of default options
     def default_results(options={})
       options.reverse_merge!(@options)