GitLab

Make sure this actually fails on posix, and return the correct error
code when trying to create a file or directory fails because the other
type already exists.

Bug: 1098001
Change-Id: I265c079a436e2107e1ee9c146e87c9e9ea3db7a1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2317989
Commit-Queue: Victor Costan <pwnall@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791450}