In this commit, we have changed behaviour of SEO dialog. Now when you keep title and description fields empty, then the page will use default title and description. We have added default_title and default_description to render the preview with default values when title and description fields are empty in SEO dialog. Task ID:1949636 closes odoo/odoo#32449 Signed-off-by: Jérémy Kersten (jke) <jke@openerp.com>