Bug 1363546 - Store and report HSTS upgrade source r=francois,keeler,mayhemer p=francois

Add a field to the HSTS cache which indicates the source of the HSTS
entry if known, from the preload list, organically seen header, or HSTS
priming, or unknown otherwise. Also adds telemetry to collect the source
when upgrading in NS_ShouldSecureUpgrade.

MozReview-Commit-ID: 3IwyYe3Cn73

docshell/base/nsDocShell.cpp

@@ -5031,10 +5031,11 @@ nsDocShell::DisplayLoadError(nsresult aError, nsIURI* aURI,
             do_GetService(NS_SSSERVICE_CONTRACTID, &rv);
           NS_ENSURE_SUCCESS(rv, rv);
           rv = sss->IsSecureURI(nsISiteSecurityService::HEADER_HSTS, aURI,
-                                flags, mOriginAttributes, nullptr, &isStsHost);
+                                flags, mOriginAttributes, nullptr, nullptr,
+                                &isStsHost);
           NS_ENSURE_SUCCESS(rv, rv);
           rv = sss->IsSecureURI(nsISiteSecurityService::HEADER_HPKP, aURI,
-                                flags, mOriginAttributes, nullptr,
+                                flags, mOriginAttributes, nullptr, nullptr,
                                 &isPinnedHost);
           NS_ENSURE_SUCCESS(rv, rv);
         } else {