Three finger swipes still work in Google Chrome. The issue you’re having is that default swipes in Lion are two fingers. Go into System Prefs, then into trackpad and change the swipes from 2 fingers to 3. You can also make it both 2 and 3 finger swipes to accomplish the same thing, in which case swiping will work in Chrome and you’ll see get the cool two finger swipes in Safari that have special animations.