Currently `deviceorientation` event is fired per platform (Hal) dispatches new data. GeckoView dispatches it per 60Hz after landing bug 1515780. This setting is same as Chrome/Android. However, This 60Hz might be still aggressive for some sites (see bug 2044630). So we add a threshold to avoid firing too many events. This threshold is same as Chrome/Android. Differential Revision: https://phabricator.services.mozilla.com/D310741