Keep pool of pre-connected DNS sockets

net/dns/dns_client.cc

Index: net/dns/dns_client.cc
diff --git a/net/dns/dns_client.cc b/net/dns/dns_client.cc
index b9c2279a140c2635dc1eb8120ee3fa0f01e86d2e..23629644cff47d6fd778f9ec4c0dce993527e993 100644
--- a/net/dns/dns_client.cc
+++ b/net/dns/dns_client.cc
@@ -10,6 +10,7 @@
 #include "net/dns/address_sorter.h"
 #include "net/dns/dns_config_service.h"
 #include "net/dns/dns_session.h"
+#include "net/dns/dns_socket_pool.h"
 #include "net/dns/dns_transaction.h"
 #include "net/socket/client_socket_factory.h"
 
@@ -29,6 +30,7 @@ class DnsClientImpl : public DnsClient {
     if (config.IsValid()) {
       session_ = new DnsSession(config,
                                 ClientSocketFactory::GetDefaultFactory(),
+                                DnsSocketPool::MakeDefault().Pass(),
                                 base::Bind(&base::RandInt),
                                 net_log_);
       factory_ = DnsTransactionFactory::CreateFactory(session_);