Steam's UpdateTouchState counts the event's `touches` per key: that count
is the pressed highlight (rgLayoutTouchCount -> Touched) and where the long
press (Backspace repeat, accents) starts. The touch-start event left the
new touch out of `touches`, like a touchend; now it is in, as in a DOM
touchstart (tracker.js touchEvent, with a test against a model of Steam's
handlers).