Add getter to SplitterState.positionReversed (#15285)

Change-Id: I1e3783d21cb5f2832838dfe36c91c7f6a4ddb313

server/src/com/vaadin/ui/AbstractSplitPanel.java

@@ -342,11 +342,25 @@ public abstract class AbstractSplitPanel extends AbstractComponentContainer {
      * Returns the unit of position of the splitter
      * 
      * @return unit of position of the splitter
+     * @see #setSplitPosition(float, Unit)
      */
     public Unit getSplitPositionUnit() {
         return posUnit;
     }
 
+    /**
+     * Is the split position reversed. By default the split position is measured
+     * by the first region, but if split position is reversed the measuring is
+     * done by the second region instead.
+     * 
+     * @since
+     * @return {@code true} if reversed, {@code false} otherwise.
+     * @see #setSplitPosition(float, boolean)
+     */
+    public boolean isSplitPositionReversed() {
+        return getSplitterState(false).positionReversed;
+    }
+
     /**
      * Sets the minimum split position to the given position and unit. If the
      * split position is reversed, maximum and minimum are also reversed.