Previously on iOS devices, tooltips in reply dialog did not always close
when clicking outside of the button. The focusOut event was not
triggered and thus _handleHideTooltip was not called. On other devices,
the tooltip remained open when clicking on it.
This change detects when a device triggers a touch event and sets a
boolean variable that it is a touch device. If touch, we do not open and
close tooltips. This was necessary because mouseenter and mouseleave
events are still triggered on touch devices with a touch.
Also, mouseover and mouseout events were replaced with mousenter and
mouseleave events because it seemed better practice since they don't
bubble to child elements & this is what is done in paper-tooltip.
Bug: Issue 4649
Change-Id: Ib3a4681e8da77a5cd7c140e3a899ceb0cf8400a8
8bb09344ab