simplify a few header includes

base/synchronization/waitable_event_posix.cc

 // 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.
 
+#include <algorithm>
+#include <vector>
+
 #include "base/synchronization/waitable_event.h"
 
 #include "base/synchronization/condition_variable.h"
 #include "base/synchronization/lock.h"
-#include "base/message_loop.h"
+#include "base/logging.h"
 
 // -----------------------------------------------------------------------------
 // A WaitableEvent on POSIX is implemented as a wait-list. Currently we don't
 // support cross-process events (where one process can signal an event which
 // others are waiting on). Because of this, we can avoid having one thread per
 // listener in several cases.
 //
 // The WaitableEvent maintains a list of waiters, protected by a lock. Each
 // waiter is either an async wait, in which case we have a Task and the
 // MessageLoop to run it on, or a blocking wait, in which case we have the
@@ skipping 373 matching lines @@
       return true;
     }
   }
 
   return false;
 }
 
 // -----------------------------------------------------------------------------
 
 }  // namespace base