Add `ActionController::Metal#set_request!`

Add `ActionController::Metal#set_request!` to set a request
on controller instance without calling dispatch.

actionpack/lib/action_controller/metal.rb

@@ -190,11 +190,15 @@ def performed?
     end
 
     def dispatch(name, request) #:nodoc:
+      set_request!(request)
+      process(name)
+      to_a
+    end
+
+    def set_request!(request) #:nodoc:
       @_request = request
       @_env = request.env
       @_env['action_controller.instance'] = self
-      process(name)
-      to_a
     end
 
     def to_a #:nodoc:

actionpack/lib/action_controller/metal/rack_delegation.rb

@@ -8,9 +8,9 @@ module RackDelegation
     delegate :headers, :status=, :location=, :content_type=,
              :status, :location, :content_type, :response_code, :to => "@_response"
 
-    def dispatch(action, request)
+    def set_request!(request) #:nodoc:
+      super
       set_response!(request)
-      super(action, request)
     end
 
     def response_body=(body)

actionpack/test/controller/new_base/bare_metal_test.rb

@@ -31,6 +31,15 @@ class BareTest < ActiveSupport::TestCase
       controller.index
       assert_equal ["Hello world"], controller.response_body
     end
+
+    test "connect a request to controller instance without dispatch" do
+      env = {}
+      controller = BareController.new
+      controller.set_request! ActionDispatch::Request.new(env)
+      assert controller.request
+      assert controller.response
+      assert env['action_controller.instance']
+    end
   end
 
   class HeadController < ActionController::Metal