The implementations have been imported into SettingsLib. Setting's copy
can now be removed, which this change also does.
Test: Manually check battery status, which uses FooterMixin, looks OK.
make RunSettingsLibRobotTests && make RunSettingsRoboTests
&& make RunSettingsGoogleRoboTests
Change-Id: I6539605fdad80d156ff5ff249e68df4a1c412067
Bug: 32642706
Bug: 32637613
Bug: 32643833
Test: RunSettingsRoboTests
This change is necessary to test preference controlling logic, as well
as making preferences reusable in other Preference pages in the new
information architecture.
Change-Id: I9e2fd2f6800579f005a5c303ed03ae06477006a6
