Make CriticalSectionWrapper non-virtual

webrtc/system_wrappers/source/critical_section_win.cc

-/*
- *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#include "webrtc/system_wrappers/source/critical_section_win.h"
-
-namespace webrtc {
-
-CriticalSectionWindows::CriticalSectionWindows() {
-  InitializeCriticalSection(&crit);
-}
-
-CriticalSectionWindows::~CriticalSectionWindows() {
-  DeleteCriticalSection(&crit);
-}
-
-void
-CriticalSectionWindows::Enter() {
-  EnterCriticalSection(&crit);
-}
-
-void
-CriticalSectionWindows::Leave() {
-  LeaveCriticalSection(&crit);
-}
-
-}  // namespace webrtc