The backport was applied incorrectly, it misses the import statement in src/windows/classes/sun/awt/windows/WToolkit.java:
import sun.awt.DisplayChangedListener;
Which causes Windows builds to fail:
Compiling 9228 files for BUILD_JDK
c:\Work\jdk8u-jdk8u-dev\jdk\src\windows\classes\sun\awt\windows\WToolkit.java:843: error: cannot find symbol
if (lge instanceof DisplayChangedListener) {
^
symbol: class DisplayChangedListener
location: class WToolkit
c:\Work\jdk8u-jdk8u-dev\jdk\src\windows\classes\sun\awt\windows\WToolkit.java:844: error: cannot find symbol
((DisplayChangedListener) lge).displayChanged();
^
symbol: class DisplayChangedListener
location: class WToolkit