VariationsService now retries over HTTP if HTTPS connection fails.

If a seed fetch over HTTP fails, Variations Service will now retry the fetch over
HTTP, encrypting the If-none-match header, and not including the
restrict parameter.

Bug: 769154
Change-Id: Ief7fd92a691110719cda5396b3bfd9c4cd402fde
Reviewed-on: https://chromium-review.googlesource.com/777723
Commit-Queue: Carlos IL <[email protected]>
Reviewed-by: Alexei Svitkine <[email protected]>
Reviewed-by: Steven Holte <[email protected]>
Reviewed-by: Emily Stark <[email protected]>
Reviewed-by: Drew Wilson <[email protected]>
Cr-Commit-Position: refs/heads/master@{#523218}
diff --git a/components/variations/variations_url_constants.cc b/components/variations/variations_url_constants.cc
index b233bb64..d97573e 100644
--- a/components/variations/variations_url_constants.cc
+++ b/components/variations/variations_url_constants.cc
@@ -10,4 +10,7 @@
 const char kDefaultServerUrl[] =
     "https://clientservices.googleapis.com/chrome-variations/seed";
 
+const char kDefaultInsecureServerUrl[] =
+    "http://clientservices.googleapis.com/chrome-variations/seed";
+
 }  // namespace variations