Only add/or remove preferences when absolutely needed.
Also fix a 'load data from backend' method that wasn't.
Fixes: 216747934
Test: ZenModeAutomaticRulesPreferenceControllerTest
Test: view schedules page
Test: add schedule
Test: remove schedule
Test: view schedule child page and return to schedules page
Change-Id: I237c2ca7ea89ee6e42354470a76712068a7f4dd7
As promised in the api docs
Test: AbstractZenModeAutomaticRulePreferenceControllerTest, view
schedule DND page
Fixes: 221423986
Change-Id: I7ddc1b112950da225afa2ba13ebf5df481922177
The notification package was getting too big.
Test: make -j64 RunSettingsRoboTests
Fixes: 145224451
Change-Id: I25ba82f42f7a137d8adcce72dcf8089d0e018bdc