Disable caching of failed DNS lookups.

This is causing problems on network changes, since we don't have a reliable signal for telling when DNS is back up (so we aren't able to flush the cache properly).

This will regress bug 1672, filed 46821 to address that.

BUG=46821

Review URL: http://codereview.chromium.org/2873003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@50141 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/net/base/host_resolver_impl.cc b/net/base/host_resolver_impl.cc
index f3bc5c1..c018a7a5 100644
--- a/net/base/host_resolver_impl.cc
+++ b/net/base/host_resolver_impl.cc
@@ -45,7 +45,7 @@
   HostCache* cache = new HostCache(
       kMaxHostCacheEntries,
       base::TimeDelta::FromMinutes(1),
-      base::TimeDelta::FromMinutes(1));
+      base::TimeDelta::FromSeconds(0));  // Disable caching of failed DNS.
 
   return cache;
 }