Refactor owner drawn buttons drawing code in wxMSW.

Move it from wxCheckBox to wxControl to allow reusing this code in other
classes, notably wxRadioButton in the upcoming commits.

See #10137.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76455 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/control.h

@@ -124,6 +124,11 @@ protected:
     // Look in our GetSubcontrols() for the windows with the given ID.
     virtual wxWindow *MSWFindItem(long id, WXHWND hWnd) const;
 
+    // For ownerdraw buttons
+    virtual bool MSWOwnerDrawnButton(const DRAWITEMSTRUCT *dis, int flags, bool isFocused);
+    virtual void MSWDrawButtonBitmap(wxWindow *WXUNUSED(win), wxDC& WXUNUSED(dc),
+                                     const wxRect& WXUNUSED(rect), int WXUNUSED(flags)) {}
+
     // for controls like radiobuttons which are really composite this array
     // holds the ids (not HWNDs!) of the sub controls
     wxArrayLong m_subControls;