[lazarus] TSPeedButton background painting

[Stephano]

As per the current implementation, TSpeedbutton's background is mostly 
dependent on themes. I would like to submit a patch that will extract the 
background painting code into a separate virtual protected method 
(TCustomSpeedButton.PaintBackground), thus allowing a descendant to control its 
background painting by overriding this method while leaving the foreground 
handling to TSpeedButton. Any input would be appreciated.

procedure TCustomSpeedButton.PaintBackground(var PaintRect: TRect);
begin
  FLastDrawDetails := GetDrawDetails;
  if not Transparent and ThemeServices.HasTransparentParts(FLastDrawDetails) 
then
  begin
    Canvas.Brush.Color := Color;
    Canvas.FillRect(PaintRect);
  end;
  ThemeServices.DrawElement(Canvas.Handle, FLastDrawDetails, PaintRect);
  PaintRect := ThemeServices.ContentRect(Canvas.Handle, FLastDrawDetails, 
PaintRect);
end;