Can pinch zoom in and out in FireFox

Finally just find out how to pinch zoom in FireFox. Just go to

 about:config

 (Search for "pinch")

browser.gesture.pinch.in
value    cmd_fullZoomReduce

browser.gesture.pinch.in.shift   
value    cmd_fullZoomReset

browser.gesture.pinch.out         
value   cmd_fullZoomEnlarge

browser.gesture.pinch.out.shift
value  cmd_fullZoomReset