move Freeze() and Thaw() to wxWindowBase to ensure that they behave consistently (i.e. recursively, as described in the docs) in all ports; removed different duplications of freeze count from derived classes

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@51018 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/toplevel.h

@@ -75,10 +75,6 @@ public:
     virtual bool SetTransparent(wxByte alpha);
     virtual bool CanSetTransparent();
 
-    //Top level windows have different freeze semantics on Windows
-    virtual void Freeze();
-    virtual void Thaw();
-
     virtual void AddChild( wxWindowBase *child );
 
 
@@ -142,6 +138,10 @@ protected:
     virtual void DoGetSize(int *width, int *height) const;
 #endif // __WXWINCE__
 
+    // Top level windows have different freeze semantics on Windows
+    virtual void DoFreeze();
+    virtual void DoThaw();
+
     // helper of SetIcons(): calls gets the icon with the size specified by the
     // given system metrics (SM_C{X|Y}[SM]ICON) from the bundle and sets it
     // using WM_SETICON with the specified wParam (ICOM_SMALL or ICON_BIG)