update_engine: UM: UpdateCheckAllowed returns target version prefix.
This piece of information is also provided by the device policy and
needed when performing the update check. Borrows logic currently in
UpdateAttempter::CalculateUpdateParams().
BUG=chromium:358269
TEST=Unit tests.
Change-Id: I5259404df1763be8944b445d51e1fafbca946306
Reviewed-on: https://chromium-review.googlesource.com/209228
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Tested-by: Gilad Arnold <garnold@chromium.org>
Commit-Queue: Gilad Arnold <garnold@chromium.org>
diff --git a/update_manager/policy.h b/update_manager/policy.h
index 9a7d620..8ec5c9e 100644
--- a/update_manager/policy.h
+++ b/update_manager/policy.h
@@ -30,6 +30,8 @@
// Attributes pertaining to the case where update checks are allowed.
//
+ // A target version prefix, if imposed by policy; otherwise, an empty string.
+ std::string target_version_prefix;
// A target channel, if so imposed by policy; otherwise, an empty string.
std::string target_channel;