Fixed somtimes focus ring is shown twice.

Fixed somtimes focus ring is shown twice.

[Title] Fixed somtimes focus ring is shown twice.
[Issue#] N/A
[Problem] Somtimes, focus ring is shown twice.
[Cause] When tap is performed in handleGestureEvent() function,
        although timer for showing focus ring has expired(focus ring had already shown and hidden),
        function to show focus ring is called again.
[Solution] When tap is performed in handleGestureEvent() function,
           if timer for showing focus ring has expired(focus ring had already shown and hidden),
           focus ring is not shown again.

Change-Id: Ia7a9802c8228d510a184c13d9cc6ae5ab670bee6