The problem occurs if the device is powered down in silent mode. When the device restarts,
AudioService reads current ringer mode from saved settings but does not call setRingerModeInt()
to perform actions required when ringer mode changes.
The volumes of streams affected by ringer mode are actually at 0 because they are also read from settings
but their mute state is not applied correclty. When we later exit from silent mode, the streams
other than STREAM_RING that are affected by ringer mode are not restored as they are not considered
muted. This applies to STREAM_SYSTEM but also to STREAM_NOTIFICATION if its volume is controlled independently
from STREAM_RING.
The fix consists in calling setRingerModeInt() when AudioService starts.
Change-Id: Ica75b9874938dda1bc1b634c3e97db4a650d295c
3891c4cc91