Implement DEPS resolution logic.

BUG=chromium:500622
TEST=unittest

Change-Id: I3efac4028c301328c22c1320a1c0dc850307160d
Reviewed-on: https://chromium-review.googlesource.com/277545
Reviewed-by: Michael Moss <mmoss@chromium.org>
Trybot-Ready: Daniel Jacques <dnj@chromium.org>
Reviewed-by: Daniel Jacques <dnj@chromium.org>
Tested-by: Daniel Jacques <dnj@chromium.org>
(cherry picked from commit a8994aa0ef05a75627e955f43821e945a99ada1e)
Reviewed-on: https://chromium-review.googlesource.com/277694
Reviewed-by: Dharani Govindan <dharani@chromium.org>
Commit-Queue: Daniel Jacques <dnj@chromium.org>
2 files changed