Fix for #6824395 introduces a new method
sun.swing.SwingUtilities2.getViewport(Component component)
which returns the parent JViewport for the passed component

CR #6878399 asks to move this method to the public API area

After additional investigation it turned out that new method
SwingUtilities.getParentViewport() will make it difficult
to make custom components compatible for both JDK 6 and JDK 7

Once a component start using SwingUtilities.getParentViewport()
it will not compile for JDK 6 any more