hg: openjfx/jfx-dev/rt: 8207942: Add new protected VirtualFlow methods for subclassing

[kevin.rushforth at oracle.com]

Changeset: f593c24b8680
Author:    shadzic
Date:      2018-12-14 17:01 -0800
URL:       http://hg.openjdk.java.net/openjfx/jfx-dev/rt/rev/f593c24b8680

8207942: Add new protected VirtualFlow methods for subclassing
Reviewed-by: kcr, nlisker, eryzhikov, aghaisas

! modules/javafx.controls/src/main/java/com/sun/javafx/scene/control/behavior/TableViewBehaviorBase.java
! modules/javafx.controls/src/main/java/javafx/scene/control/skin/ListViewSkin.java
! modules/javafx.controls/src/main/java/javafx/scene/control/skin/TableColumnHeader.java
! modules/javafx.controls/src/main/java/javafx/scene/control/skin/TableHeaderRow.java
! modules/javafx.controls/src/main/java/javafx/scene/control/skin/TableViewSkin.java
! modules/javafx.controls/src/main/java/javafx/scene/control/skin/TableViewSkinBase.java
! modules/javafx.controls/src/main/java/javafx/scene/control/skin/TreeTableViewSkin.java
! modules/javafx.controls/src/main/java/javafx/scene/control/skin/TreeViewSkin.java
! modules/javafx.controls/src/main/java/javafx/scene/control/skin/VirtualFlow.java
! modules/javafx.controls/src/shims/java/javafx/scene/control/skin/VirtualFlowShim.java
+ modules/javafx.controls/src/test/java/test/javafx/scene/control/skin/VirtualFlowSubClassTest.java