qquickitemchangelistener_p.h: add a comment for the sake of clarity

QQuickItemChangeListener::itemGeometryChanged() used to have two QRectF
arguments, which were the new and old geometries. In commit e2c296c the
remaining QRectF argument was changed to a diff of the geometry change.
The meaning of the unnamed argument is not obvious from the method
signature, so add an explanatory comment similar to 83cd7c2.

Change-Id: I62043b3399a86be3490e48c83cedff4f9d630652
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>
Reviewed-by: Robin Burchell <robin.burchell@viroteck.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/quick/items/qquickitemchangelistener_p.h b/src/quick/items/qquickitemchangelistener_p.h
index 7a4949fc0b..19ff73056b 100644
--- a/src/quick/items/qquickitemchangelistener_p.h
+++ b/src/quick/items/qquickitemchangelistener_p.h
@@ -120,7 +120,7 @@ class QQuickItemChangeListener
 public:
     virtual ~QQuickItemChangeListener() {}
 
-    virtual void itemGeometryChanged(QQuickItem *, QQuickGeometryChange, const QRectF &) {}
+    virtual void itemGeometryChanged(QQuickItem *, QQuickGeometryChange, const QRectF & /* diff */) {}
     virtual void itemSiblingOrderChanged(QQuickItem *) {}
     virtual void itemVisibilityChanged(QQuickItem *) {}
     virtual void itemOpacityChanged(QQuickItem *) {}