1 files changed, 60 insertions, 1 deletions
diff --git a/cc/completion_event.h b/cc/completion_event.h
index 638cbb2..462e4ba 100644
--- a/cc/completion_event.h
+++ b/cc/completion_event.h
@@ -1,3 +1,62 @@
-// Copyright 2012 The Chromium Authors. All rights reserved.
+// Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
+
+#ifndef CCCompletionEvent_h
+#define CCCompletionEvent_h
+
+#include "base/synchronization/waitable_event.h"
+
+namespace cc {
+
+// Used for making blocking calls from one thread to another. Use only when
+// absolutely certain that doing-so will not lead to a deadlock.
+//
+// It is safe to destroy this object as soon as wait() returns.
+class CCCompletionEvent {
+public:
+    CCCompletionEvent()
+        : m_event(false /* manual_reset */, false /* initially_signaled */)
+    {
+#ifndef NDEBUG
+        m_waited = false;
+        m_signaled = false;
+#endif
+    }
+
+    ~CCCompletionEvent()
+    {
+        ASSERT(m_waited);
+        ASSERT(m_signaled);
+    }
+
+    void wait()
+    {
+        ASSERT(!m_waited);
+#ifndef NDEBUG
+        m_waited = true;
+#endif
+        m_event.Wait();
+    }
+
+    void signal()
+    {
+        ASSERT(!m_signaled);
+#ifndef NDEBUG
+        m_signaled = true;
+#endif
+        m_event.Signal();
+    }
+
+private:
+    base::WaitableEvent m_event;
+#ifndef NDEBUG
+    // Used to assert that wait() and signal() are each called exactly once.
+    bool m_waited;
+    bool m_signaled;
+#endif
+};
+
+}
+
+#endif