Move empty_dll, scoped_file and test_strings to the Chromium repo

Bug: 830892
Change-Id: I0621b9b69cd84e539231e535562f7c34b75fa1ca
Reviewed-on: https://chromium-review.googlesource.com/1136941
Commit-Queue: Chris Sharp <csharp@chromium.org>
Reviewed-by: Joe Mason <joenotcharles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575412}
6 files changed