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

Source/platform/geometry/FloatSize.h

 /*
  * Copyright (C) 2003, 2006 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) 2005 Nokia.  All rights reserved.
  *               2008 Eric Seidel <eric@webkit.org>
  *
  * 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.
@@ skipping 13 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef FloatSize_h
 #define FloatSize_h
 
 #include "platform/geometry/IntPoint.h"
 #include "wtf/MathExtras.h"
 
-
 #if OS(MACOSX)
 typedef struct CGSize CGSize;
 
-#ifdef NSGEOMETRY_TYPES_SAME_AS_CGGEOMETRY_TYPES
-typedef struct CGSize NSSize;
-#else
-typedef struct _NSSize NSSize;
+#ifdef __OBJC__
+#import <Foundation/Foundation.h>
 #endif
 #endif
 
 namespace WebCore {
 
 class IntSize;
 class LayoutSize;
 
 class PLATFORM_EXPORT FloatSize {
 public:
@@ skipping 49 matching lines @@
     }
 
     FloatSize transposedSize() const
     {
         return FloatSize(m_height, m_width);
     }
 
 #if OS(MACOSX)
     explicit FloatSize(const CGSize&); // don't do this implicitly since it's lossy
     operator CGSize() const;
-#if !defined(NSGEOMETRY_TYPES_SAME_AS_CGGEOMETRY_TYPES)
+#if defined(__OBJC__) && !defined(NSGEOMETRY_TYPES_SAME_AS_CGGEOMETRY_TYPES)
     explicit FloatSize(const NSSize &); // don't do this implicitly since it's lossy
     operator NSSize() const;
 #endif
 #endif
 
 private:
     float m_width, m_height;
 };
 
 inline FloatSize& operator+=(FloatSize& a, const FloatSize& b)
@@ skipping 61 matching lines @@
 }
 
 inline IntPoint flooredIntPoint(const FloatSize& p)
 {
     return IntPoint(clampToInteger(floorf(p.width())), clampToInteger(floorf(p.height())));
 }
 
 } // namespace WebCore
 
 #endif // FloatSize_h