Remove deprecated NonThreadSafe usage in net\socket.

net/socket/tcp_socket_win.h

Index: net/socket/tcp_socket_win.h
diff --git a/net/socket/tcp_socket_win.h b/net/socket/tcp_socket_win.h
index a553e37122518c3b09e657d9a4c6c9bd9a36ec5c..1c1b548490e03d0d397395c4548367913778c4f4 100644
--- a/net/socket/tcp_socket_win.h
+++ b/net/socket/tcp_socket_win.h
@@ -13,7 +13,7 @@
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
-#include "base/threading/non_thread_safe.h"
+#include "base/threading/thread_checker.h"
 #include "base/win/object_watcher.h"
 #include "net/base/address_family.h"
 #include "net/base/completion_callback.h"
@@ -30,8 +30,7 @@ class IPEndPoint;
 class NetLog;
 struct NetLogSource;
 
-class NET_EXPORT TCPSocketWin : NON_EXPORTED_BASE(public base::NonThreadSafe),
-                                public base::win::ObjectWatcher::Delegate  {
+class NET_EXPORT TCPSocketWin : public base::win::ObjectWatcher::Delegate {
  public:
   TCPSocketWin(
       std::unique_ptr<SocketPerformanceWatcher> socket_performance_watcher,
@@ -186,6 +185,8 @@ class NET_EXPORT TCPSocketWin : NON_EXPORTED_BASE(public base::NonThreadSafe),
 
   NetLogWithSource net_log_;
 
+  THREAD_CHECKER(thread_checker_);
+
   DISALLOW_COPY_AND_ASSIGN(TCPSocketWin);
 };