title: getHistorySize() returns 0 even on MotionEvent.ACTION_MOVE events
body: <p>I kept getting 0 from event.getHistorySize() even when the event is MotionEvent.ACTION_MOVE. </p>
  
  <p>However, it's not always zero. It adds one point count in like 10 ACTION_MOVE events. Can anyone please help?</p>