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.cc

@@ -0,0 +1,104 @@
+/*
+ *  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.
+ */
+
+#include "webrtc/system_wrappers/include/trace.h"
+#include "webrtc/system_wrappers/source/condition_variable_native_win.h"
+#include "webrtc/system_wrappers/source/critical_section_win.h"
+
+namespace webrtc {
+
+static HMODULE library = NULL;
+static bool win_support_condition_variables_primitive = false;
+
+PInitializeConditionVariable  PInitializeConditionVariable_;
+PSleepConditionVariableCS     PSleepConditionVariableCS_;
+PWakeConditionVariable        PWakeConditionVariable_;
+PWakeAllConditionVariable     PWakeAllConditionVariable_;
+
+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);
+
+ConditionVariableNativeWin::ConditionVariableNativeWin() {
+}
+
+ConditionVariableNativeWin::~ConditionVariableNativeWin() {
+}
+
+ConditionVariableWrapper* ConditionVariableNativeWin::Create() {
+  ConditionVariableNativeWin* ret_val = new ConditionVariableNativeWin();
+  if (!ret_val->Init()) {
+    delete ret_val;
+    return NULL;
+  }
+  return ret_val;
+}
+
+bool ConditionVariableNativeWin::Init() {
+  if (!library) {
+    // Native implementation is supported on Vista+.
+    library = LoadLibrary(TEXT("Kernel32.dll"));
+    // TODO(henrike): this code results in an attempt to load the above dll
+    // every time the previous attempt failed. Only try to load once.
+    if (library) {
+      // TODO(henrike): not thread safe as reading and writing to library is not
+      // serialized. Fix.
+      WEBRTC_TRACE(kTraceStateInfo, kTraceUtility, -1, "Loaded Kernel.dll");
+
+      PInitializeConditionVariable_ =
+          (PInitializeConditionVariable) GetProcAddress(
+              library, "InitializeConditionVariable");
+      PSleepConditionVariableCS_ = (PSleepConditionVariableCS) GetProcAddress(
+          library, "SleepConditionVariableCS");
+      PWakeConditionVariable_ = (PWakeConditionVariable) GetProcAddress(
+          library, "WakeConditionVariable");
+      PWakeAllConditionVariable_ = (PWakeAllConditionVariable) GetProcAddress(
+          library, "WakeAllConditionVariable");
+
+      if (PInitializeConditionVariable_ && PSleepConditionVariableCS_
+          && PWakeConditionVariable_ && PWakeAllConditionVariable_) {
+        WEBRTC_TRACE(
+            kTraceStateInfo, kTraceUtility, -1,
+            "Loaded native condition variables");
+        win_support_condition_variables_primitive = true;
+      }
+    }
+  }
+  if (!win_support_condition_variables_primitive) {
+    return false;
+  }
+  PInitializeConditionVariable_(&condition_variable_);
+  return true;
+}
+
+void ConditionVariableNativeWin::SleepCS(CriticalSectionWrapper& crit_sect) {
+  SleepCS(crit_sect, INFINITE);
+}
+
+bool ConditionVariableNativeWin::SleepCS(CriticalSectionWrapper& crit_sect,
+                                         unsigned long max_time_in_ms) {
+  CriticalSectionWindows* cs =
+      static_cast<CriticalSectionWindows*>(&crit_sect);
+  BOOL ret_val = PSleepConditionVariableCS_(&condition_variable_,
+                                            &(cs->crit), max_time_in_ms);
+  return ret_val != 0;
+}
+
+void ConditionVariableNativeWin::Wake() {
+  PWakeConditionVariable_(&condition_variable_);
+}
+
+void ConditionVariableNativeWin::WakeAll() {
+  PWakeAllConditionVariable_(&condition_variable_);
+}
+
+}  // namespace webrtc