autotest: end-to-end autoupdate test

This implements an autotest test for the Chrome OS autoupdate
functionality.  It receives a single test configuration and performs an
end-to-end test of the update process specified by it, which includes:

* Initializing the DUT to a known start state (source version)

* Spawning a local Omaha/devserver instance.

* Triggering an update process.

* Tracking the progress of the update.

* Rebooting the DUT after the update.

* Ensuring that the update has succeeded (target version running).

BUG=chromium-os:33760,chromium-os:33761,chromium-os:33762
TEST=Running with run_remote_tests.sh works

Change-Id: I215e8214d3239f525f062a27a4d97806451c9736
Reviewed-on: https://gerrit.chromium.org/gerrit/37432
Commit-Ready: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Gilad Arnold <garnold@chromium.org>
Tested-by: Gilad Arnold <garnold@chromium.org>
diff --git a/global_config.ini b/global_config.ini
index a3b09c9..b1fd919 100644
--- a/global_config.ini
+++ b/global_config.ini
@@ -146,6 +146,9 @@
 image_url_pattern: %s/update/%s
 package_url_pattern: %s/static/archive/%s/autotest/packages
 log_url_pattern: http://%s/tko/retrieve_logs.cgi?job=/results/%s/
+delta_payload_url_pattern: %s/static/%s-release/%s-%s/au/%s-%s_%s/update.gz
+full_payload_url_pattern: %s/static/%s-release/%s-%s/update.gz
+test_image_url_pattern: %s/static/images/%s-release/%s-%s/chromiumos_test_image.bin
 # Username and password for connecting to remote power control switches of
 # the "Sentry Switched CDU" type
 rpm_sentry_username: fake_user