Rename OS(DARWIN) to OS(MACOSX).

Source/core/platform/graphics/IntPoint.h

Index: Source/core/platform/graphics/IntPoint.h
diff --git a/Source/core/platform/graphics/IntPoint.h b/Source/core/platform/graphics/IntPoint.h
index 97489d867ef0ef12593d281d97c5bf2aaf6d4b20..80746c4bfb8007ce5a67a5296fd80cd2f42ba532 100644
--- a/Source/core/platform/graphics/IntPoint.h
+++ b/Source/core/platform/graphics/IntPoint.h
@@ -30,7 +30,7 @@
 #include "core/platform/graphics/IntSize.h"
 #include "wtf/MathExtras.h"
 
-#if OS(DARWIN)
+#if OS(MACOSX)
 typedef struct CGPoint CGPoint;
 #ifdef NSGEOMETRY_TYPES_SAME_AS_CGGEOMETRY_TYPES
 typedef struct CGPoint NSPoint;
@@ -88,7 +88,7 @@ public:
         return IntPoint(m_y, m_x);
     }
 
-#if OS(DARWIN)
+#if OS(MACOSX)
     explicit IntPoint(const CGPoint&); // don't do this implicitly since it's lossy
     operator CGPoint() const;