Make CriticalSectionWrapper non-virtual

webrtc/system_wrappers/source/critical_section_posix.cc

-/*
- *  Copyright (c) 2012 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.
- */
-
-// General note: return values for the various pthread synchronization APIs
-// are explicitly ignored here. In Chromium, the same thing is done for release.
-// However, in debugging, failure in these APIs are logged.
-// TODO(henrike): add logging when pthread synchronization APIs are failing.
-
-#include "webrtc/system_wrappers/source/critical_section_posix.h"
-
-namespace webrtc {
-
-CriticalSectionPosix::CriticalSectionPosix() {
-  pthread_mutexattr_t attr;
-  (void) pthread_mutexattr_init(&attr);
-  (void) pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
-  (void) pthread_mutex_init(&mutex_, &attr);
-}
-
-CriticalSectionPosix::~CriticalSectionPosix() {
-  (void) pthread_mutex_destroy(&mutex_);
-}
-
-void
-CriticalSectionPosix::Enter() {
-  (void) pthread_mutex_lock(&mutex_);
-}
-
-void
-CriticalSectionPosix::Leave() {
-  (void) pthread_mutex_unlock(&mutex_);
-}
-
-}  // namespace webrtc