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diff --git a/Source/WTF/wtf/CrossThreadQueue.h b/Source/WTF/wtf/CrossThreadQueue.h
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+++ b/Source/WTF/wtf/CrossThreadQueue.h
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+/*
+ * Copyright (C) 2016 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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 with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <limits>
+#include <wtf/Assertions.h>
+#include <wtf/Condition.h>
+#include <wtf/Deque.h>
+#include <wtf/Lock.h>
+#include <wtf/Noncopyable.h>
+#include <wtf/Optional.h>
+#include <wtf/Threading.h>
+
+namespace WTF {
+
+template<typename DataType>
+class CrossThreadQueue {
+    WTF_MAKE_NONCOPYABLE(CrossThreadQueue);
+public:
+    CrossThreadQueue() = default;
+
+    void append(DataType&&);
+
+    DataType waitForMessage();
+    std::optional<DataType> tryGetMessage();
+
+    bool isKilled() const { return false; }
+
+private:
+    mutable Lock m_lock;
+    Condition m_condition;
+    Deque<DataType> m_queue;
+};
+
+template<typename DataType>
+void CrossThreadQueue<DataType>::append(DataType&& message)
+{
+    LockHolder lock(m_lock);
+    m_queue.append(WTFMove(message));
+    m_condition.notifyOne();
+}
+
+template<typename DataType>
+DataType CrossThreadQueue<DataType>::waitForMessage()
+{
+    LockHolder lock(m_lock);
+
+    auto found = m_queue.end();
+    while (found == m_queue.end()) {
+        found = m_queue.begin();
+        if (found != m_queue.end())
+            break;
+
+        m_condition.wait(m_lock);
+    }
+
+    return m_queue.takeFirst();
+}
+
+template<typename DataType>
+std::optional<DataType> CrossThreadQueue<DataType>::tryGetMessage()
+{
+    LockHolder lock(m_lock);
+
+    if (m_queue.isEmpty())
+        return { };
+
+    return m_queue.takeFirst();
+}
+
+} // namespace WTF
+
+using WTF::CrossThreadQueue;