allocate request objects with the env hash, set routes on the request

This commit is to abstract the code away from the env hash.  It no
longer needs to have the routes key hard coded.

actionpack/lib/action_controller/metal.rb

@@ -140,13 +140,6 @@ module ActionController
       end
     end
 
-    def self.build_with_env(env = {}) #:nodoc:
-      new.tap { |c|
-        c.set_request! ActionDispatch::Request.new(env)
-        c.set_response! make_response!(c.request)
-      }
-    end
-
     # Delegates to the class' <tt>controller_name</tt>
     def controller_name
       self.class.controller_name

actionpack/lib/action_controller/renderer.rb

@@ -65,14 +65,18 @@ module ActionController
       @controller = controller
       @defaults = defaults
       @env = normalize_keys defaults.merge(env)
-      @env['action_dispatch.routes'] = controller._routes
     end
 
     # Render templates with any options from ActionController::Base#render_to_string.
     def render(*args)
       raise 'missing controller' unless controller
 
-      instance = controller.build_with_env(@env)
+      request = ActionDispatch::Request.new @env
+      request.routes = controller._routes
+
+      instance = controller.new
+      instance.set_request! request
+      instance.set_response! controller.make_response!(request)
       instance.render_to_string(*args)
     end