GitLab

This CL updates the CrosUsbDetector to ignore failed mount events.
Currently USB drives with filesystems we can't mount are not able to be
shared with VMs as it attempts and fails to unmount disks which were
never successfully mounted in the first place.

Bug: 1146325
Change-Id: I56001e5039d609a5eac1c037c83f9cf474e7ff20
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2583600Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Commit-Queue: Timothy Loh <timloh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835907}