smbprovider: Add auth params for MountOptionsProto

Adds workgroup and username for MountOptionsProto.

BUG=chromium:757625
TEST=emerges
Change-Id: I3aa02847dc882107cfa38eace977c51f92a41a61
Reviewed-on: https://chromium-review.googlesource.com/981048
Commit-Ready: Allen Vicencio <allenvic@chromium.org>
Tested-by: Allen Vicencio <allenvic@chromium.org>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
1 file changed