supporting content size scaling (retina display)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67001 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/osx/window.h

@@ -266,6 +266,9 @@ public:
     virtual bool        OSXHandleKeyEvent( wxKeyEvent& event );
 
     bool                IsNativeWindowWrapper() const { return m_isNativeWindowWrapper; }
+    
+    float               GetContentScaleFactor() const ;
+    
 protected:
     // For controls like radio buttons which are genuinely composite
     wxList              m_subControls;