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

base/synchronization/waitable_event.h

-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 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 BASE_WAITABLE_EVENT_H_
-#define BASE_WAITABLE_EVENT_H_
+#ifndef BASE_SYNCHRONIZATION_WAITABLE_EVENT_H_
+#define BASE_SYNCHRONIZATION_WAITABLE_EVENT_H_
 #pragma once
 
 #include "base/basictypes.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 
 #if defined(OS_POSIX)
 #include <list>
@@ skipping 152 matching lines @@
   typedef std::pair<WaitableEvent*, size_t> WaiterAndIndex;
   static size_t EnqueueMany(WaiterAndIndex* waitables,
                             size_t count, Waiter* waiter);
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(WaitableEvent);
 };
 
 }  // namespace base
 
-#endif  // BASE_WAITABLE_EVENT_H_
+#endif  // BASE_SYNCHRONIZATION_WAITABLE_EVENT_H_