device/fido/mac: fix a threading bug in TouchIdContext

TouchIdContext implements the Touch ID authorization prompt. After
receiving the OS reply callback from the Security framework it forwards
the result to the user-supplied callback, but doesn't do so on the
original TaskRunner that it was invoked on. As a result, Touch ID
authenticator requests fail some sequence checker tests. This fixes that
by posting the user-supplied callback back on the original runner.

Bug: 678128
Change-Id: I0e7a8730ec898f288cd25323134aa95ef50ddbdf
Commit-Queue: Martin Kreichgauer <>
Reviewed-by: Robert Sesek <>
Reviewed-by: Kim Paulhamus <>
Cr-Commit-Position: refs/heads/master@{#575361}
7 files changed