use swipehelper to determine scroll

let swipe helper determine if the user meant to scroll
fixes b/7022556 Increase scroll threshold gets rid of leave behind
If we use the scroll listener, we don't get to use our own threshhold
We want to be careful when the user has started on the leave behind item
and make sure that we dont just detect the user playing around on the item,
maybe just a touch for "what did I do here?" and dismiss it by accident
So the threshhold for dismissing the item when the user starts on the
leavebehinditem is larger than when they start on another item.

Change-Id: I1e55e6c9be07e026b19a4ad55ad531305d3777d2
6 files changed