Allow VirtualADB control VHCI state.

This change makes VirtualUSB more robust by detecting cases where device
is gone. The effect is that ADB will re-attach to device after it comes
back online, instead of reporting it as 'offline'.

Change-Id: Ib37a5273043ba42c47c8bf4a1f52f15152d05af7
(cherry picked from commit f4f38a878415365bf4d554641e880cd37935bb68)
10 files changed