WifiScanningServiceImpl: Handle race on iface removal

If there is a scan completion event as the iface is being removed,
mScannerImpls will contain an empty list when trying to report the
results. Return a scan failure instead because we can't fetch the real scan
results since the iface is no longer there.

Bug: 142469675
Test: atest com.android.server.wifi.scanner

Change-Id: I673e7562196fdb9660e74c520478a10ad5d05e45
2 files changed
tree: a7a43829b6288a64b842abac0c098f495f283c39
  1. service/
  2. PREUPLOAD.cfg