[Mac] Rely on science, not chance, to get the proper definition of the macro

Source/platform/geometry/FloatPoint.h

 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc.  All rights reserved.
  * Copyright (C) 2005 Nokia.  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
@@ skipping 17 matching lines @@
 #define FloatPoint_h
 
 #include "platform/geometry/FloatSize.h"
 #include "platform/geometry/IntPoint.h"
 #include "wtf/MathExtras.h"
 #include <algorithm>
 
 #if OS(MACOSX)
 typedef struct CGPoint CGPoint;
 
-#ifdef NSGEOMETRY_TYPES_SAME_AS_CGGEOMETRY_TYPES
-typedef struct CGPoint NSPoint;
-#else
-typedef struct _NSPoint NSPoint;
+#ifdef __OBJC__
+#import <Foundation/Foundation.h>
 #endif
 #endif
 
 struct SkPoint;
 
 namespace WebCore {
 
 class IntPoint;
 class IntSize;
 class LayoutPoint;
@@ skipping 74 matching lines @@
     }
 
     FloatPoint transposedPoint() const
     {
         return FloatPoint(m_y, m_x);
     }
 
 #if OS(MACOSX)
     FloatPoint(const CGPoint&);
     operator CGPoint() const;
-#if !defined(NSGEOMETRY_TYPES_SAME_AS_CGGEOMETRY_TYPES)
+#if defined(__OBJC__) && !defined(NSGEOMETRY_TYPES_SAME_AS_CGGEOMETRY_TYPES)
     FloatPoint(const NSPoint&);
     operator NSPoint() const;
 #endif
 #endif
 
     operator SkPoint() const;
 
 private:
     float m_x, m_y;
 };
@@ skipping 84 matching lines @@
 }
 
 PLATFORM_EXPORT float findSlope(const FloatPoint& p1, const FloatPoint& p2, float& c);
 
 // Find point where lines through the two pairs of points intersect. Returns false if the lines don't intersect.
 PLATFORM_EXPORT bool findIntersection(const FloatPoint& p1, const FloatPoint& p2, const FloatPoint& d1, const FloatPoint& d2, FloatPoint& intersection);
 
 }
 
 #endif