Clearing mDestroying flag when app is made visible again

If not cleared window will remain invisible and can't receive inputs,
which coud lead to ANR.

Also continue looking for windows to be destroyed instead of stopping
on first one that's not removed by client.

bug: 27123118
Change-Id: I27048779886c69eb6e7ad5e21210be511416d8b6
1 file changed