No real changes, just change type of MSWGetBgBrush() argument.

Pass wxWindow instead of HWND to it as in most cases we already have wxWindow
for the HWND we have and calling wxFindWinFromHandle() once more is
unnecessary.

This also makes the code of MSWGetBgBrushForChild() slightly simpler.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62932 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/notebook.h

@@ -183,7 +183,7 @@ public:
   }
 
   // return the themed brush for painting our children
-  virtual WXHBRUSH MSWGetBgBrushForChild(WXHDC hDC, WXHWND hWnd);
+  virtual WXHBRUSH MSWGetBgBrushForChild(WXHDC hDC, wxWindow *child);
 
   // draw child background
   virtual bool MSWPrintChild(WXHDC hDC, wxWindow *win);