WP_Customize_Manager::filter_iframe_security_headers PHP Method

    public function filter_iframe_security_headers($headers)
    {
        $customize_url = admin_url('customize.php');
        $headers['X-Frame-Options'] = 'ALLOW-FROM ' . $customize_url;
        $headers['Content-Security-Policy'] = 'frame-ancestors ' . preg_replace('#^(\\w+://[^/]+).+?$#', '$1', $customize_url);
        return $headers;
    }

 /**
  * Test WP_Customize_Manager::filter_iframe_security_headers().
  *
  * @ticket 30937
  * @covers WP_Customize_Manager::filter_iframe_security_headers()
  */
 function test_filter_iframe_security_headers()
 {
     $customize_url = admin_url('customize.php');
     $wp_customize = new WP_Customize_Manager();
     $headers = $wp_customize->filter_iframe_security_headers(array());
     $this->assertArrayHasKey('X-Frame-Options', $headers);
     $this->assertArrayHasKey('Content-Security-Policy', $headers);
     $this->assertEquals("ALLOW-FROM {$customize_url}", $headers['X-Frame-Options']);
 }