Move DefaultSerializer from array_serializer.rb to serializer.rb

lib/active_model/serializer.rb

@@ -387,4 +387,20 @@ module ActiveModel
       ActiveSupport::Notifications.instrument(event_name, payload, &block)
     end
   end
+  
+  # DefaultSerializer
+  #
+  # Provides a constant interface for all items, particularly
+  # for ArraySerializer.
+  class DefaultSerializer
+    attr_reader :object, :options
+
+    def initialize(object, options={})
+      @object, @options = object, options
+    end
+
+    def serializable_hash
+      @object.as_json
+    end
+  end
 end