Added auto-fill support for DatePicker and TimePicker.

Also fixed some getAutoFillType() implementations to return null
when the view is disabled.

Bug: 33550221
Bug: 35840787
Test: CtsAutoFillServiceTestCases (with new tests) pass
Test: m update-api

Change-Id: I46acc1fb106cf2153515cc1c9567b34cfabd1c62