twig.xml

<?xml version="1.0" ?>

<container xmlns="http://symfony.com/schema/dic/services"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">

    <parameters>
        <parameter key="mobile_detect.twig.extension.class"/>
    </parameters>

    <services>
        <service id="mobile_detect.twig.extension" class="%mobile_detect.twig.extension.class%">
            <argument type="service" id="mobile_detect.mobile_detector" />
            <argument type="service" id="mobile_detect.device_view" />
            <argument>%mobile_detect.redirect%</argument>
            <call method="setRequestByRequestStack">
                <argument type="service" id="request_stack" on-invalid="null" />
            </call>
            <tag name="twig.extension"/>
        </service>
    </services>
</container>