the logic in PR is already found in Tracker\Request overrideLocation($visitorInfo);

Calling this method will also bring country, region, city, lat, long overrides. Cheers

overrideLocation() only allows to pass lat/long in request in case when current request is first action of visit.
Any following action will not change visit's lat/long.
This PR purpose is to allow update lat/long in any following action of visit (for example for mobile users).

overrideLocation will override the following:

    static $locationOverrideParams = array(
        'country' => array('string', 'location_country'),
        'region'  => array('string', 'location_region'),
        'city'    => array('string', 'location_city'),
        'lat'     => array('float', 'location_latitude'),
        'long'    => array('float', 'location_longitude'),
    );

So it does also country / region / city. My feedback is to use this function rather than rewrite the code only for lat/long.