Code Review Request For JDK-8090185: Ubuntu: switching to fullscreen from primary stage in browser displays grey screen

[Chien Yang]

Hi Kevin,

Please review the proposed fix as we have investigated yesterday:

The fix is to check and handle correctly when there is change in the 
underlaying nativeWindow. This is the case happened on Linux when we do 
fullscreen in Applet mode.

Passed dev-build-lite run on Linux and Mac.

JIRA: https://bugs.openjdk.java.net/browse/JDK-8090185
Webrev: http://cr.openjdk.java.net/~ckyang/JDK-8090185/webrev.00/
Thanks,
- Chien