Implement ReadDirectory for SmbFileSystem

Implements ReadDirectory for SmbFileSystem. This will allow the files
app to be able to populate entries when inside a directory.

Bug: chromium:757625
Change-Id: I972bc19a0791acf607f181dd4d051c5b6d4ed9d4
Reviewed-on: https://chromium-review.googlesource.com/824912
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Commit-Queue: Allen Vicencio <allenvic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#525390}
2 files changed