Rename OS(DARWIN) to OS(MACOSX).

Source/core/platform/Scrollbar.cpp

 /*
  * Copyright (C) 2004, 2006, 2008 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 24 matching lines @@
 #include "core/platform/graphics/GraphicsContext.h"
 
 // FIXME: The following #includes are a layering violation and should be removed.
 #include "core/accessibility/AXObjectCache.h"
 #include "core/page/EventHandler.h"
 #include "core/page/Frame.h"
 #include "core/page/FrameView.h"
 
 using namespace std;
 
-#if OS(UNIX) && !OS(DARWIN)
+#if OS(UNIX) && !OS(MACOSX)
 // The position of the scrollbar thumb affects the appearance of the steppers, so
 // when the thumb moves, we have to invalidate them for painting.
 #define THUMB_POSITION_AFFECTS_BUTTONS
 #endif
 
 namespace WebCore {
 
 PassRefPtr<Scrollbar> Scrollbar::create(ScrollableArea* scrollableArea, ScrollbarOrientation orientation, ScrollbarControlSize size)
 {
     return adoptRef(new Scrollbar(scrollableArea, orientation, size));
@@ skipping 539 matching lines @@
     if (!m_scrollableArea)
         return 0;
 
     if (m_orientation == HorizontalScrollbar)
         return m_scrollableArea->scrollPosition().x() - m_scrollableArea->minimumScrollPosition().x();
 
     return m_scrollableArea->scrollPosition().y() - m_scrollableArea->minimumScrollPosition().y();
 }
 
 } // namespace WebCore