Make SSLClientSessionCacheOpenSSL thread-safe.

net/ssl/ssl_client_session_cache_openssl.h

 // Copyright 2015 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.
 
 #ifndef NET_SSL_SSL_CLIENT_SESSION_CACHE_OPENSSL_H
 #define NET_SSL_SSL_CLIENT_SESSION_CACHE_OPENSSL_H
 
 #include <openssl/ssl.h>
 
 #include <string>
 
 #include "base/containers/mru_cache.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/synchronization/lock.h"
 #include "base/threading/thread_checker.h"
 #include "base/time/time.h"
 #include "net/base/net_export.h"
 #include "net/ssl/scoped_openssl_types.h"
 
 namespace base {
 class Clock;
 }
 
 namespace net {
@@ skipping 50 matching lines @@
   bool IsExpired(CacheEntry* entry, const base::Time& now);
 
   // Removes all expired sessions from the cache.
   void FlushExpiredSessions();
 
   scoped_ptr<base::Clock> clock_;
   Config config_;
   CacheEntryMap cache_;
   size_t lookups_since_flush_;
 
-  base::ThreadChecker thread_checker_;
+  // TODO(davidben): After https://crbug.com/458365 is fixed, replace this with
+  // a ThreadChecker. The session cache should be single-threaded like other
+  // classes in net.
+  base::Lock lock_;
 
   DISALLOW_COPY_AND_ASSIGN(SSLClientSessionCacheOpenSSL);
 };
 
 }  // namespace net
 
 #endif  // NET_SSL_SSL_CLIENT_SESSION_CACHE_OPENSSL_H