Use TouchPointManager method "hasValidPoint" to made code more readable.

Substituting new TouchPointManager method instead of calculating
directly in QuickContactActivity.
When a point is initialized, its value is (0,0), since it is highly
unlikely a user will touch at that exact point, we define a valid point
as any point that is not (0,0).

Bug: 17124195
Change-Id: Ie6ca75a76d2068314fbf746d4b3711425ac4e28f