pos/pos_default_empty_image/view/view.xml

<?xml version="1.0" encoding="UTF-8"?>
<openerp>
    <data>
        <template id="assets_backend" name="pos_default_empty_image assets" inherit_id="web.assets_backend">
            <xpath expr="." position="inside">
                <script type="text/javascript" src="/pos_default_empty_image/static/src/js/pos_default_empty_image.js"></script>
            </xpath>
        </template>
    </data>
</openerp>