Will this be part of the core code any time soon?

I tried using this with Vaadin Framework 8.6.3 and it doesn’t add the icon on the button, it’s still above the button.
Here is the code I used

@SpringUI(path = "upload")
public class UploadUI extends UI {
    @Override
    protected void init(VaadinRequest request) {
        Layout layout = new HorizontalLayout();
        layout.addComponent(uploadButton());
        setContent(layout);
    }

    private UploadButton uploadButton() {
        UploadButton button = new UploadButton();
        button.setButtonCaption("Upload");
        button.setIcon(VaadinIcons.UPLOAD, "");
        return button;
    }
}

Here is how it looks

If I try with caption as html with the following code

@SpringUI(path = "upload")
public class UploadUI extends UI {
    @Override
    protected void init(VaadinRequest request) {
        Layout layout = new HorizontalLayout();
        layout.addComponent(uploadButton());
        setContent(layout);
    }

    private UploadButton uploadButton() {
        UploadButton button = new UploadButton();
        button.setCaptionAsHtml(true);
        button.setButtonCaption(VaadinIcons.UPLOAD.getHtml() + "Upload");
        return button;
    }
}

I get the following result

Am I doing something wrong? Any chance to fix this and add the icon on the button?

Did you recompile the widgetset?