Polish the Number/Date/Pickers per UX request.

1. Now the NumberPicker max height is a bit smaller.

2. The Time/Date picker add top and bottom margin to
   compensate for the shorter NumberPickers.

3. The Time/DatePicker dialogs have only "Done" button
   and tapping onside saves the current state.

bug:6277808

Change-Id: I4c5928debb1c3b7fe126d6cd6745e3c5eb980901