Mark SIGKILL exits as potentially flaky, and propagate them up.

Currently, we don't propagate up errors in the case where a
SIGKILL exit was flaky. Do this.

BUG=chromium:308196
TEST=New unit test.

Change-Id: I49b2f1d0f0e0e0dc9641001f7dfa2bcc079389ac
Reviewed-on: https://chromium-review.googlesource.com/175515
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: David James <davidjames@chromium.org>
Tested-by: David James <davidjames@chromium.org>
2 files changed