[8] Review request for 8004298 NPE in WindowsTreeUI.ensureRowsAreVisible

[Alexander Scherbatiy]

Hello,

Could you review the fix:
  bug: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8004298
  webrev: http://cr.openjdk.java.net/~alexsch/8004298/webrev.00

  The getPathBounds() method can return null under certain circumstances.
  The fix checks this before using the testRect variable.

Thanks,
Alexandr.