The Manager now loops through known challenge types, trying to fulfill one at a time until it succeeds or runs out of supported challenges. The provisioning of "http-01" challenges can be done using the new Manager.HTTPHandler method. It requires listening on unencrypted port 80. Fixes golang/go#21890 Change-Id: I55de9501f0069a9f460fedd8b5b0a09b94f9ef05 Reviewed-on: https://go-review.googlesource.com/87201 Run-TryBot: Alex Vaghin <ddos@google.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>