Add chromium-depot_tools.  It's DESCR:

Chromium and Chromium OS use a package of scripts called depot_tools
to manage checkouts and code reviews.  The depot_tools package
includes gclient, gcl, git-cl, repo, and others.

This for now allows us to run the wip/v8 tests.
Fix a few nits.  Yes, I should have run pkglint earlier.