connector-telephony/base_phone/web_phone.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  © 2014-2016 Akretion (Alexis de Lattre <alexis.delattre@akretion.com>)
  License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
-->

<odoo>
<data>


<template id="assets_backend" name="base_phone assets"
          inherit_id="web.assets_backend">
    <xpath expr="." position="inside">
        <script type="text/javascript"
            src="/base_phone/static/lib/phonenumbers/PhoneFormat.js"></script>
        <script type="text/javascript"
            src="/base_phone/static/src/js/phone_widget.js"></script>
    </xpath>
</template>


</data>
</odoo>