bug 981513 - revert 807441 r=sworkman

--HG--
extra : rebase_source : d2c219fe01b6e4e0fdf25b920df0091039cf4c18

netwerk/dns/nsHostResolver.cpp

@@ -602,7 +602,7 @@ nsHostResolver::ResolveHost(const char            *host,
                 result = he->rec;
                 Telemetry::Accumulate(Telemetry::DNS_LOOKUP_METHOD2, METHOD_HIT);
 
-                // For entries that are in the grace period with a failed connect,
+                // For entries that are in the grace period
                 // or all cached negative entries, use the cache but start a new
                 // lookup in the background
                 ConditionallyRefreshRecord(he->rec, host);
@@ -886,9 +886,8 @@ nsHostResolver::IssueLookup(nsHostRecord *rec)
 nsresult
 nsHostResolver::ConditionallyRefreshRecord(nsHostRecord *rec, const char *host)
 {
-    if ((((TimeStamp::NowLoRes() > rec->expiration) &&
-        rec->mBlacklistedItems.Length()) ||
-        rec->negative) && !rec->resolving) {
+    if (((TimeStamp::NowLoRes() > rec->expiration) || rec->negative) &&
+        !rec->resolving) {
         LOG(("  Using %s cache entry for host [%s] but starting async renewal.",
             rec->negative ? "negative" :"positive", host));
         IssueLookup(rec);