Move CancellationFlag and WaitableEvent to the synchronization subdirectory....

base/cancellation_flag.h

-// Copyright (c) 2010 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 BASE_CANCELLATION_FLAG_H_
-#define BASE_CANCELLATION_FLAG_H_
-#pragma once
-
-#include "base/atomicops.h"
-#include "base/threading/platform_thread.h"
-
-namespace base {
-
-// CancellationFlag allows one thread to cancel jobs executed on some worker
-// thread. Calling Set() from one thread and IsSet() from a number of threads
-// is thread-safe.
-//
-// This class IS NOT intended for synchronization between threads.
-class CancellationFlag {
- public:
-  CancellationFlag() : flag_(false) {
-#if !defined(NDEBUG)
-    set_on_ = PlatformThread::CurrentId();
-#endif
-  }
-  ~CancellationFlag() {}
-
-  // Set the flag. May only be called on the thread which owns the object.
-  void Set();
-  bool IsSet() const;  // Returns true iff the flag was set.
-
- private:
-  base::subtle::Atomic32 flag_;
-#if !defined(NDEBUG)
-  PlatformThreadId set_on_;
-#endif
-
-  DISALLOW_COPY_AND_ASSIGN(CancellationFlag);
-};
-
-}  // namespace base
-
-#endif  // BASE_CANCELLATION_FLAG_H_