web_window_title/views/webclient_templates.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>
        <template id="layout" inherit_id="web.layout" name="web_window_title custom">
            <xpath expr="//title" position="replace">
                <title><t t-esc="title or 'Odoo'"/></title>
            </xpath>
        </template>
        <template id="assets_backend" inherit_id="web.assets_backend" name="web_window_title assets">
            <xpath expr="." position="inside">
                <script type="text/javascript" src="/web_window_title/static/src/js/web_window_title.js"/>
            </xpath>
        </template>
    </data>
</openerp>