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diff --git a/include/base/cef_atomic_ref_count.h b/include/base/cef_atomic_ref_count.h
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+// Copyright (c) 2014 Marshall A. Greenblatt. Portions copyright (c) 2011
+// Google 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:
+//
+//    * 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 with the
+// distribution.
+//    * Neither the name of Google Inc. nor the name Chromium Embedded
+// Framework nor the names of its contributors may be used to endorse
+// or promote products derived from this software without specific prior
+// written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
+// OWNER OR 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.
+
+// This is a low level implementation of atomic semantics for reference
+// counting.  Please use cef_ref_counted.h directly instead.
+//
+// The Chromium implementation includes annotations to avoid some false
+// positives when using data race detection tools. Annotations are not
+// currently supported by the CEF implementation.
+
+#ifndef CEF_INCLUDE_BASE_CEF_ATOMIC_REF_COUNT_H_
+#define CEF_INCLUDE_BASE_CEF_ATOMIC_REF_COUNT_H_
+#pragma once
+
+#if defined(USING_CHROMIUM_INCLUDES)
+// When building CEF include the Chromium header directly.
+#include "base/atomic_ref_count.h"
+
+#else  // !USING_CHROMIUM_INCLUDES
+// The following is substantially similar to the Chromium implementation.
+// If the Chromium implementation diverges the below implementation should be
+// updated to match.
+
+#include <atomic>
+
+namespace base {
+
+class AtomicRefCount {
+ public:
+  constexpr AtomicRefCount() : ref_count_(0) {}
+  explicit constexpr AtomicRefCount(int initial_value)
+      : ref_count_(initial_value) {}
+
+  ///
+  /// Increment a reference count.
+  /// Returns the previous value of the count.
+  ///
+  int Increment() { return Increment(1); }
+
+  ///
+  /// Increment a reference count by "increment", which must exceed 0.
+  /// Returns the previous value of the count.
+  ///
+  int Increment(int increment) {
+    return ref_count_.fetch_add(increment, std::memory_order_relaxed);
+  }
+
+  ///
+  /// Decrement a reference count, and return whether the result is non-zero.
+  /// Insert barriers to ensure that state written before the reference count
+  /// became zero will be visible to a thread that has just made the count zero.
+  ///
+  bool Decrement() {
+    // TODO(jbroman): Technically this doesn't need to be an acquire operation
+    // unless the result is 1 (i.e., the ref count did indeed reach zero).
+    // However, there are toolchain issues that make that not work as well at
+    // present (notably TSAN doesn't like it).
+    return ref_count_.fetch_sub(1, std::memory_order_acq_rel) != 1;
+  }
+
+  ///
+  /// Return whether the reference count is one.  If the reference count is used
+  /// in the conventional way, a refrerence count of 1 implies that the current
+  /// thread owns the reference and no other thread shares it.  This call
+  /// performs the test for a reference count of one, and performs the memory
+  /// barrier needed for the owning thread to act on the object, knowing that it
+  /// has exclusive access to the object.
+  ///
+  bool IsOne() const { return ref_count_.load(std::memory_order_acquire) == 1; }
+
+  ///
+  /// Return whether the reference count is zero.  With conventional object
+  /// referencing counting, the object will be destroyed, so the reference count
+  /// should never be zero.  Hence this is generally used for a debug check.
+  ///
+  bool IsZero() const {
+    return ref_count_.load(std::memory_order_acquire) == 0;
+  }
+
+  ///
+  /// Returns the current reference count (with no barriers). This is subtle,
+  /// and should be used only for debugging.
+  ///
+  int SubtleRefCountForDebug() const {
+    return ref_count_.load(std::memory_order_relaxed);
+  }
+
+ private:
+  std::atomic_int ref_count_;
+};
+
+}  // namespace base
+
+#endif  // !USING_CHROMIUM_INCLUDES
+
+#endif  // CEF_INCLUDE_BASE_CEF_ATOMIC_REF_COUNT_H_