Added WindowData structures to GraphicsWindowX11,Win32 and Carbon to help support

GraphicsWindow inheriting their window handles from an external toolkit

include/osgViewer/GraphicsWindowCarbon

@@ -32,13 +32,14 @@ class GraphicsWindowCarbon : public osgViewer::GraphicsWindow
     public:
 
         GraphicsWindowCarbon(osg::GraphicsContext::Traits* traits):
+            _ownWindow(true),
             _valid(false),
             _initialized(false),
             _realized(false)
         {
             _traits = traits;
 
-            init();
+            init(traits ? dynamic_cast<WindowData*>(traits->inheritedWindowData.get()) : 0);
             
             if (valid())
             {
@@ -98,9 +99,18 @@ class GraphicsWindowCarbon : public osgViewer::GraphicsWindow
         bool handleMouseEvent(EventRef theEvent);
         bool handleKeyboardEvent(EventRef theEvent);
 
+        /** WindowData is used to pass in the X11 window handle attached the GraphicsContext::Traits structure. */
+        struct WindowData : public osg::Referenced
+        {
+            WindowData(Window window):
+                _window(window) {}
+                
+            Window          _window;
+        };
+
     protected:
     
-        void init();
+        void init(WindowData* inheritedWindowData=0);
         
         void transformMouseXY(float& x, float& y);
         
@@ -111,6 +121,7 @@ class GraphicsWindowCarbon : public osgViewer::GraphicsWindow
         bool            _realized;
         bool            _useWindowDecoration;
 
+        bool            _ownsWindow;
         WindowRef       _window;
         AGLContext      _context;
         AGLPixelFormat  _pixelFormat;