This is a reland of 822dbc51

Skia has fixed the test.

Original change's description:
> Reland "gclient: Require a target ref when applying patches."
>
> This is a reland of 1d6478a5
>
> Original change's description:
> > gclient: Require a target ref when applying patches.
> >
> > Bug: 956807
> > Change-Id: Icfffe965f9f4651f22e8ba32c60133a5620bb350
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1616804
> > Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
> > Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
>
> Bug: 956807
> Change-Id: I3de8475a091ce6a2a14ff7dcfb92507a205ef78c
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1623594
> Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
> Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

TBR=tandrii@chromium.org

Bug: 956807
Change-Id: Ie273dafb921206f6346678c1861320129ad5b6fd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1649695Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>