Variations service now checks explicitely if previous attempt was HTTP.

Variations service now sets a flag if the last request was an HTTP
retry, and uses it to decide whether to retry again, instead of
relying on the scheme of the final URL. Also, retries are now disabled
if the fallback url is HTTPS.

Bug: 902727
Change-Id: Ibd6df4a22bc6302b231aff0ae32f8e1c8a1f277c
Reviewed-on: https://chromium-review.googlesource.com/c/1325035
Commit-Queue: Carlos IL <carlosil@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607022}
3 files changed