Root UID can synthesize AttributionSource values.

We trust any incoming value from the system UID, so we should also
trust values coming from the root UID, which includes many shell
commands such as "svc".

Bug: 193659633
Test: atest BluetoothInstrumentationTests:com.android.bluetooth.btservice.AdapterServiceTest --rerun-until-failure 100
Change-Id: Ied07731345f08fc3c4df465a3773e35c8df7c59a
1 file changed