Import ConditionVariable class.

src/platform/mutex.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 76 matching lines @@
   const NativeHandle& native_handle() const V8_WARN_UNUSED_RESULT {
     return native_handle_;
   }
 
  private:
   NativeHandle native_handle_;
 #ifdef DEBUG
   int level_;
 #endif
 
+  V8_INLINE(void AssertHeldAndUnmark()) {
+#ifdef DEBUG
+    ASSERT_EQ(1, level_);
+    level_--;
+#endif
+  }
+
+  V8_INLINE(void AssertUnheldAndMark()) {
+#ifdef DEBUG
+    ASSERT_EQ(0, level_);
+    level_++;
+#endif
+  }
+
+  friend class ConditionVariable;
+
   DISALLOW_COPY_AND_ASSIGN(Mutex);
 };
 
 
 // POD Mutex initialized lazily (i.e. the first time Pointer() is called).
 // Usage:
 //   static LazyMutex my_mutex = LAZY_MUTEX_INITIALIZER;
 //
 //   void my_function() {
 //     LockGuard<Mutex> guard(my_mutex.Pointer());
@@ skipping 107 matching lines @@
  private:
   Mutex* mutex_;
 
   LockGuard(const LockGuard<Mutex>& other) V8_DELETE;
   LockGuard<Mutex>& operator=(const LockGuard<Mutex>& other) V8_DELETE;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_PLATFORM_MUTEX_H_