smbprovider: Add SmbProviderClient

Add Mount and Unmount.

CQ-DEPEND=CL:782708

Bug: chromium:757625
Change-Id: Idbc9ccc80da7872317f3a0bd05b72447e09de1d0
Reviewed-on: https://chromium-review.googlesource.com/745304
Commit-Queue: Allen Vicencio <allenvic@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>
Reviewed-by: Lutz Justen <ljusten@chromium.org>
Reviewed-by: Roman Sorokin <rsorokin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#519507}
9 files changed