update_engine: UM: Add P2P download limits to UpdateCanStart.
This adds two factors that are currently used for blocking P2P into the
Chrome OS policy implementation: a maximum number of P2P download
attempts and a maximum time period since the first attempt.
BUG=chromium:420732
TEST=Unit tests.
Change-Id: I430dec50cf07f37a0c3f14de3410d3c6bfb8ac78
Reviewed-on: https://chromium-review.googlesource.com/221735
Reviewed-by: David Zeuthen <zeuthen@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Tested-by: Gilad Arnold <garnold@chromium.org>
Commit-Queue: Gilad Arnold <garnold@chromium.org>
5 files changed