Three more attempts to get metal look.

- Added a few flags for inheriting background.
     - Added wxWindow param to wxR::DrawBackground()
     - Added wxR::DrawButtonSurface()
     - Removed wxR::DrawBackground() from wxR::DrawButtonBorder()
     - Adde DrawMetal to Metal theme
  Fixed minor bug in wxGTK scrollbar.
  Changed code in wxX11 wxTLW so that startup flicker no
    longer occurs in wxFrame.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@15136 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/univ/button.h

@@ -109,6 +109,8 @@ protected:
                                long numArg = -1,
                                const wxString& strArg = wxEmptyString);
     virtual wxSize DoGetBestClientSize() const;
+    
+    virtual bool DoDrawBackground(wxDC& dc);
     virtual void DoDraw(wxControlRenderer *renderer);
 
     virtual bool CanBeHighlighted() const { return TRUE; }