Merge change 1708 into donut

* changes:
  Fixes #1853550. Prevent NPE when calling the PopupWindow() and PopupWindow(int, int) constructors. Instead, throw an IllegalStateException when trying to show a popup with no content view.
tree: 2db88e9f1a42bf5dfbbe01580a6e8071666179e9
  1. awt/
  2. camera/
  3. cmds/
  4. im/
  5. include/
  6. libs/
  7. opengl/
  8. MODULE_LICENSE_APACHE2
  9. NOTICE