Update include/base headers for C++11/14 (see issue #3140)

See the issue for update guidelines.

include/base/cef_atomic_flag.h

@@ -0,0 +1,87 @@
+// 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.
+
+#ifndef CEF_INCLUDE_BASE_CEF_ATOMIC_FLAG_H_
+#define CEF_INCLUDE_BASE_CEF_ATOMIC_FLAG_H_
+#pragma once
+
+#if defined(USING_CHROMIUM_INCLUDES)
+// When building CEF include the Chromium header directly.
+#include "base/synchronization/atomic_flag.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 <stdint.h>
+
+#include <atomic>
+
+#include "include/base/cef_macros.h"
+#include "include/base/cef_thread_checker.h"
+
+namespace base {
+
+// A flag that can safely be set from one thread and read from other threads.
+//
+// This class IS NOT intended for synchronization between threads.
+class AtomicFlag {
+ public:
+  AtomicFlag();
+  ~AtomicFlag();
+
+  // Set the flag. Must always be called from the same thread.
+  void Set();
+
+  // Returns true iff the flag was set. If this returns true, the current thread
+  // is guaranteed to be synchronized with all memory operations on the thread
+  // which invoked Set() up until at least the first call to Set() on it.
+  bool IsSet() const {
+    // Inline here: this has a measurable performance impact on base::WeakPtr.
+    return flag_.load(std::memory_order_acquire) != 0;
+  }
+
+  // Resets the flag. Be careful when using this: callers might not expect
+  // IsSet() to return false after returning true once.
+  void UnsafeResetForTesting();
+
+ private:
+  std::atomic<uint_fast8_t> flag_{0};
+  base::ThreadChecker set_thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(AtomicFlag);
+};
+
+}  // namespace base
+
+#endif  // !USING_CHROMIUM_INCLUDES
+
+#endif  // CEF_INCLUDE_BASE_CEF_ATOMIC_FLAG_H_