<Swing Dev> [13] RFR JDK-8215396: JTabbedPane preferred size calculation is wrong for SCROLL_TAB_LAYOUT

[Prasanta Sadhukhan]

Hi All,

Please review a fix for an issue where it is seen that for 
SCROLL_TAB_LAYOUT the border of the content of JTabbedPane is not fully 
shown, whereas for WRAP_TAB_LAYOUT policy, the content is fully shown.

It seems BasicTabbedPaneUI.TabbedPaneScrollLayout inner class (used for 
SCROLL_TAB_LAYOUT) has preferredTabAreaHeight() and 
preferredTabAreaWidth() which are overridden from
its superclass, BasicTabbedPaneUI.TabbedPaneLayout (used for 
WRAP_TAB_LAYOUT). In superclass, these methods take into account the tab 
area insets, but the overridden methods in TabbedPaneScrollLayout  don't.

Proposed fix is to use existing methods 
[calculateTabAreaHeight,calculateTabAreaWidth] for calculating the size 
as was done for WRAP_TAB_LAYOUT.

Bug: https://bugs.openjdk.java.net/browse/JDK-8215396
webrev: http://cr.openjdk.java.net/~psadhukhan/8215396/webrev.0/

Regards
Prasanta