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

net/socket/ssl_client_socket_nss.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.
 
 // This file includes code SSLClientSocketNSS::DoVerifyCertComplete() derived
 // from AuthCertificateCallback() in
 // mozilla/security/manager/ssl/src/nsNSSCallbacks.cpp.
 
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
@@ skipping 45 matching lines @@
 #include <secerr.h>
 #include <sechash.h>
 #include <ssl.h>
 #include <sslerr.h>
 #include <sslproto.h>
 
 #include <limits>
 
 #include "base/compiler_specific.h"
 #include "base/metrics/histogram.h"
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/nss_util.h"
-#include "base/singleton.h"
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
 #include "base/thread_restrictions.h"
 #include "base/values.h"
 #include "net/base/address_list.h"
 #include "net/base/cert_status_flags.h"
 #include "net/base/cert_verifier.h"
 #include "net/base/connection_type_histograms.h"
 #include "net/base/dns_util.h"
@@ skipping 99 matching lines @@
 
     // All other SSL options are set per-session by SSLClientSocket.
   }
 
   ~NSSSSLInitSingleton() {
     // Have to clear the cache, or NSS_Shutdown fails with SEC_ERROR_BUSY.
     SSL_ClearSessionCache();
   }
 };
 
+static base::LazyInstance<NSSSSLInitSingleton> g_nss_ssl_init_singleton(
+    base::LINKER_INITIALIZED);
+
 // Initialize the NSS SSL library if it isn't already initialized.  This must
 // be called before any other NSS SSL functions.  This function is
 // thread-safe, and the NSS SSL library will only ever be initialized once.
 // The NSS SSL library will be properly shut down on program exit.
 void EnsureNSSSSLInit() {
   // Initializing SSL causes us to do blocking IO.
   // Temporarily allow it until we fix
   //   http://code.google.com/p/chromium/issues/detail?id=59847
   base::ThreadRestrictions::ScopedAllowIO allow_io;
 
-  Singleton<NSSSSLInitSingleton>::get();
+  g_nss_ssl_init_singleton.Get();
 }
 
 // The default error mapping function.
 // Maps an NSPR error code to a network error code.
 int MapNSPRError(PRErrorCode err) {
   // TODO(port): fill this out as we learn what's important
   switch (err) {
     case PR_WOULD_BLOCK_ERROR:
       return ERR_IO_PENDING;
     case PR_ADDRESS_NOT_SUPPORTED_ERROR:  // For connect.
@@ skipping 2398 matching lines @@
     case SSL_CONNECTION_VERSION_TLS1_1:
       UpdateConnectionTypeHistograms(CONNECTION_SSL_TLS1_1);
       break;
     case SSL_CONNECTION_VERSION_TLS1_2:
       UpdateConnectionTypeHistograms(CONNECTION_SSL_TLS1_2);
       break;
   };
 }
 
 }  // namespace net