[550389] Convert Sirius diagram to ELK graph - No label for border node

There was no label exported for a border node with label located outside
the border node.

Bug: 550389
Cherry-picked-from: 548820
Change-Id: I0628bf5b637d4ceaef530f5575d8cc0f0a56f8e8
Signed-off-by: Laurent Redor <laurent.redor@obeo.fr>
diff --git a/plugins/org.eclipse.sirius.diagram.elk/src/org/eclipse/sirius/diagram/elk/ElkDiagramLayoutConnector.java b/plugins/org.eclipse.sirius.diagram.elk/src/org/eclipse/sirius/diagram/elk/ElkDiagramLayoutConnector.java
index 3ca53c2..88d6b0c 100644
--- a/plugins/org.eclipse.sirius.diagram.elk/src/org/eclipse/sirius/diagram/elk/ElkDiagramLayoutConnector.java
+++ b/plugins/org.eclipse.sirius.diagram.elk/src/org/eclipse/sirius/diagram/elk/ElkDiagramLayoutConnector.java
@@ -864,6 +864,9 @@
                     text = ((WrappingLabel) labelFigure).getText();
                 } else if (labelFigure instanceof Label) {
                     text = ((Label) labelFigure).getText();
+                } else if (labelFigure instanceof SiriusWrapLabel) {
+                    SiriusWrapLabel label = (SiriusWrapLabel) labelFigure;
+                    text = label.getText();
                 }
 
                 if (text != null) {