Refactor SmbFileSystem to use default callback

Refactor duplicated callback methods into a default status callback.

Bug: chromium:757625
Change-Id: Ib38d1582eaa480a1faacce6654ac210606ea3c5d
Reviewed-on: https://chromium-review.googlesource.com/916824
Commit-Queue: Allen Vicencio <allenvic@chromium.org>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#536546}
2 files changed