Properly handle cancel event in GlowPadView

There was a workaround used in a previous release where we effectively
ignored cancel events to work around another bug.  This change removes
the workaround and GlowPadView correctly handles the event.

Bug 6903638

Change-Id: I9b510985c6da346a4e10cf2535267c8d5efa5871
1 file changed