AM::Serializers::Xml depends on AM::Naming

activemodel/lib/active_model/serializers/xml.rb

@@ -10,6 +10,10 @@ module ActiveModel
       extend ActiveSupport::Concern
       include ActiveModel::Serialization
 
+      included do
+        extend ActiveModel::Naming
+      end
+
       class Serializer #:nodoc:
         class Attribute #:nodoc:
           attr_reader :name, :value, :type

activemodel/test/cases/serializers/json_serialization_test.rb

@@ -4,7 +4,6 @@ require 'models/automobile'
 require 'active_support/core_ext/object/instance_variables'
 
 class Contact
-  extend ActiveModel::Naming
   include ActiveModel::Serializers::JSON
   include ActiveModel::Validations
 

activemodel/test/cases/serializers/xml_serialization_test.rb

@@ -4,7 +4,6 @@ require 'active_support/core_ext/object/instance_variables'
 require 'ostruct'
 
 class Contact
-  extend ActiveModel::Naming
   include ActiveModel::Serializers::Xml
 
   attr_accessor :address, :friends
@@ -25,7 +24,6 @@ class Customer < Struct.new(:name)
 end
 
 class Address
-  extend ActiveModel::Naming
   include ActiveModel::Serializers::Xml
 
   attr_accessor :street, :city, :state, :zip, :apt_number

activemodel/test/models/contact.rb

@@ -1,5 +1,4 @@
 class Contact
-  extend ActiveModel::Naming
   include ActiveModel::Conversion
 
   attr_accessor :id, :name, :age, :created_at, :awesome, :preferences