Build xwl using Docker

Change-Id: I032ececf17878a7fc88de4b18d7b1f393667d132
Reviewed-on: https://chromium-review.googlesource.com/966895
Reviewed-by: Stephen Barber <smbarber@chromium.org>
Tested-by: Stephen Barber <smbarber@chromium.org>
2 files changed