code: @Override
      public final Viewport add(final Scene scene)
      {
          if ((null != scene) && (LienzoCore.IS_CANVAS_SUPPORTED))
          {
              if (false == scene.adopt(this))
              {
                  throw new IllegalArgumentException("Scene is already adopted.");
              }
              if (length() > 2)
              {
                  throw new IllegalArgumentException("Too many Scene objects is Viewport.");
              }
              final DivElement element = scene.getElement();
  
              scene.setPixelSize(m_wide, m_high);
  
              element.getStyle().setPosition(Position.ABSOLUTE);
  
              element.getStyle().setDisplay(Display.INLINE_BLOCK);
  
              getElement().appendChild(element);
  
              super.add(scene);
          }
          return this;
      }
docs: Adds a {@link Scene} to this viewport.
  
  @param scene