Adding datepicker in GuidedStepFragment

Add GuidedDatePickerAction.  Added a new VIEW_TYPE_DATE_PICKER in
GuidedActionsStylist to handle GuidedDatePickerAction.  The behavior
is abstracted as a "click to activate/deactivate" widget, allowing
subclass to support action other than DatePicker.  The transition
shares same code for drop down list (i.e. sub actions).

Fix the generic Builder class problem, passing the concrete Builder
class as generic parameter.

Switch Picker to use standard activated status from a customized
"expanded" attribute.

And API review changes

Bug: 25390757
Bug: 26509683
Bug: 26509387
Bug: 26509381

Change-Id: I35cb5f99a1e81acaa51366cf17b1353180c7a549
12 files changed