Reject SMB URLs that don't have a share name.

Although these are valid URLs, they cause Samba to browse the server,
which isn't a supported use case (yet). Instead, reject them and show
the user the same error as other invalid URLs.

BUG=907207

Change-Id: I287363cf71504f624c27e42e5a0af1adfe5c4c30
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1532129
Commit-Queue: Anand Mistry <amistry@chromium.org>
Reviewed-by: Bailey Berro <baileyberro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#643189}
6 files changed