Remove drupal_add_css() and drupal_add_js() from the ajax system

Looks good.

From AjaxResponse->ajaxRender:

foreach (array('css', 'js') as $type) {
      // It is highly suspicious if $_POST['ajax_page_state'][$type] is empty,
      // since the base page ought to have at least one JS file and one CSS file
      // loaded. It probably indicates an error, and rather than making the page
      // reload all of the files, instead we return no new files.
      if (empty($ajax_page_state[$type])) {
        $items[$type] = array();
      }
      else {
        $function = 'drupal_add_' . $type;
        $items[$type] = $function();
        drupal_alter($type, $items[$type]);
        // @todo Inline CSS and JS items are indexed numerically. These can't be
        //   reliably diffed with array_diff_key(), since the number can change
        //   due to factors unrelated to the inline content, so for now, we
        //   strip the inline items from Ajax responses, and can add support for
        //   them when drupal_add_css() and drupal_add_js() are changed to use
        //   a hash of the inline content as the array key.
        foreach ($items[$type] as $key => $item) {
          if (is_numeric($key)) {
            unset($items[$type][$key]);
          }
        }
        // Ensure that the page doesn't reload what it already has.
        $items[$type] = array_diff_key($items[$type], $ajax_page_state[$type]);
      }
    }

This should be handled as well.

Re-roll + addressing #5

Locally test is fine. So 10: 2095335-ajax-10.patch queued for re-testing.

Sorry testbot, it was my fault...

Changes in #15 looks good to me, so +1 for RTBC.

Just a question:

+++ b/core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.module
@@ -569,7 +569,6 @@ function ajax_forms_test_lazy_load_form_submit($form, &$form_state) {
-    $form['#attached'] = $attached;

As per #5, addd this line. Can we re move drupal_render() and keep $form['#attached']? will that make any difference? or better way of doing?

Committed ff4a8e9 and pushed to 8.x. Thanks!