NativeBridge: Tighten security on libnativebridge

Do not allow arbitrary paths for the native bridge - only allow
simple names.

Do not allow re-setup of the native bridge.

Bug: 16404669

(cherry picked from commit cd2ef4c1af69727231b84ebc82864c170ff0e8ad)

Change-Id: Ie22de356d2307fe2758f9094a85d44e61a4098a1
9 files changed