Migrate git eclasses to eclass-overlay

Multiple copies of these eclasses exist between portage-stable and
chromiumos-overlay. We want to move them here so that only one version
of these eclasses is ever used and needs to be maintained.

All three eclasses were taken from portage-stable. git-2.eclass was
amended to allow EAPI 6 for this migration, as the version in
chromiumos-overlay did not have this restriction.

BUG=chromium:989082
TEST=precq

Cq-Depend: chrome-internal:1549011
Change-Id: I66a115ff549ebe9b6d61b18029c8a5431e802d2e
Reviewed-on: https://chromium-review.googlesource.com/1725151
Tested-by: Chris McDonald <cjmcdonald@chromium.org>
Commit-Ready: Chris McDonald <cjmcdonald@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
3 files changed
tree: ff5a696bebd8fb0a2e0332bd51c8317fa19c3150
  1. eclass/
  2. metadata/
  3. profiles/
  4. OWNERS
  5. PRESUBMIT.cfg