Rely on SystemService#onSwitchUser() in TSMS.

SystemService class has already provided SystemService#onSwitchUser()
callback event.  We do not need to set up SynchronousUserSwitchObserver
separately in TextServicesManagerService.

Bug: 25816558
Bug: 27456430
Change-Id: I2d6f9932f30b72cf4ae4bc0c41810f75e2667478
1 file changed