Make members of Singleton<T> private and only visible to the singleton type.

net/socket/client_socket_factory.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/socket/client_socket_factory.h"
 
-#include "base/singleton.h"
+#include "base/lazy_instance.h"
 #include "build/build_config.h"
 #include "net/socket/client_socket_handle.h"
 #if defined(OS_WIN)
 #include "net/socket/ssl_client_socket_win.h"
 #elif defined(USE_OPENSSL)
 #include "net/socket/ssl_client_socket_openssl.h"
 #elif defined(USE_NSS)
 #include "net/socket/ssl_client_socket_nss.h"
 #elif defined(OS_MACOSX)
 #include "net/socket/ssl_client_socket_nss.h"
@@ skipping 46 matching lines @@
       ClientSocketHandle* transport_socket,
       const HostPortPair& host_and_port,
       const SSLConfig& ssl_config,
       SSLHostInfo* ssl_host_info,
       DnsCertProvenanceChecker* dns_cert_checker) {
     return g_ssl_factory(transport_socket, host_and_port, ssl_config,
                          ssl_host_info, dns_cert_checker);
   }
 };
 
+static base::LazyInstance<DefaultClientSocketFactory>
+    g_default_client_socket_factory(base::LINKER_INITIALIZED);
+
 }  // namespace
 
 // static
 ClientSocketFactory* ClientSocketFactory::GetDefaultFactory() {
-  return Singleton<DefaultClientSocketFactory>::get();
+  return g_default_client_socket_factory.Pointer();
 }
 
 // static
 void ClientSocketFactory::SetSSLClientSocketFactory(
     SSLClientSocketFactory factory) {
   g_ssl_factory = factory;
 }
 
 // Deprecated function (http://crbug.com/37810) that takes a ClientSocket.
 SSLClientSocket* ClientSocketFactory::CreateSSLClientSocket(
     ClientSocket* transport_socket,
     const HostPortPair& host_and_port,
     const SSLConfig& ssl_config,
     SSLHostInfo* ssl_host_info) {
   ClientSocketHandle* socket_handle = new ClientSocketHandle();
   socket_handle->set_socket(transport_socket);
   return CreateSSLClientSocket(socket_handle, host_and_port, ssl_config,
                                ssl_host_info,
                                NULL /* DnsCertProvenanceChecker */);
 }
 
 }  // namespace net