Add missing windows conditions variable

Those are used by generic RW lock implementation.

https://bugs.freedesktop.org/show_bug.cgi?id=96754

webrtc/system_wrappers/source/condition_variable_native_win.h

@@ -0,0 +1,54 @@
+/*
+ *  Copyright (c) 2013 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.
+ */
+
+#ifndef WEBRTC_SYSTEM_WRAPPERS_SOURCE_CONDITION_VARIABLE_NATIVE_WIN_H_
+#define WEBRTC_SYSTEM_WRAPPERS_SOURCE_CONDITION_VARIABLE_NATIVE_WIN_H_
+
+#include <windows.h>
+
+#include "webrtc/system_wrappers/include/condition_variable_wrapper.h"
+
+namespace webrtc {
+
+#if !defined CONDITION_VARIABLE_INIT
+typedef struct RTL_CONDITION_VARIABLE_ {
+  void* Ptr;
+} RTL_CONDITION_VARIABLE, *PRTL_CONDITION_VARIABLE;
+
+typedef RTL_CONDITION_VARIABLE CONDITION_VARIABLE, *PCONDITION_VARIABLE;
+#endif
+
+typedef void (WINAPI* PInitializeConditionVariable)(PCONDITION_VARIABLE);
+typedef BOOL (WINAPI* PSleepConditionVariableCS)(PCONDITION_VARIABLE,
+                                                 PCRITICAL_SECTION, DWORD);
+typedef void (WINAPI* PWakeConditionVariable)(PCONDITION_VARIABLE);
+typedef void (WINAPI* PWakeAllConditionVariable)(PCONDITION_VARIABLE);
+
+class ConditionVariableNativeWin : public ConditionVariableWrapper {
+ public:
+  static ConditionVariableWrapper* Create();
+  virtual ~ConditionVariableNativeWin();
+
+  void SleepCS(CriticalSectionWrapper& crit_sect);
+  bool SleepCS(CriticalSectionWrapper& crit_sect, unsigned long max_time_inMS);
+  void Wake();
+  void WakeAll();
+
+ private:
+  ConditionVariableNativeWin();
+
+  bool Init();
+
+  CONDITION_VARIABLE condition_variable_;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_SYSTEM_WRAPPERS_SOURCE_CONDITION_VARIABLE_NATIVE_WIN_H_