<Swing Dev> Review request for 4473075: JTable header rendering problem (after setting preferred size)

[Semyon Sadetsky]

Hello,

please review a fix for JDK 9.

Bug: https://bugs.openjdk.java.net/browse/JDK-4473075
Webrev: 
http://cr.openjdk.java.net/~alexsch/semyon-sadetsky/4473075/webrev.00/

The thing is the general logic of the viewport layout requires the right 
component size which is requested by the getPreferredSize call to the 
child component.
The right width of JTableHeader should be calculated in its UI but if 
user sets the preferred size manually it makes the calculated size 
invisible outside the component. User may need to set preferred size in 
order to adjust header height but in setPreferredSize(Dimension) the 
header width is adjusted as well.
The fix solution overrides JComponent::getPreferredSize in JTableHeader 
with the logic returning the right width while preserving the height 
adjustable for user.