GitLab

Adds some simple tests to ensure imported constants and constants
specified in terms of other constants have the correct values.

The CL used to do more, but https://crrev.com/c/2204846 made it all
redundant.

Bug: 1002798,1008761
Change-Id: I2de4b945848c8b4ad358fbcd296189c8d989cbfc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1839752Reviewed-by: Ken Rockot <rockot@google.com>
Commit-Queue: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Cr-Commit-Position: refs/heads/master@{#772490}