Zen mode change will call displayPreference() and create a new SettingsObserver, then the old Observer object will have no opportunity to be unregistered. After too much new SettingsObserver creatd in Monkey test, memory might leak.
Bug 176206489
Change-Id: I3bccec281da492299bbf755f86df7844a31223c5
The notification package was getting too big.
Test: make -j64 RunSettingsRoboTests
Fixes: 145224451
Change-Id: I25ba82f42f7a137d8adcce72dcf8089d0e018bdc