QmlDesigner: Add isValidQmlPropertyChanges

Change-Id: Ib859c10fc17148822e18c2d4e03c229ae6f8230d
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>

src/plugins/qmldesigner/designercore/include/qmlchangeset.h

@@ -53,6 +53,7 @@ public:
     QmlPropertyChanges() : QmlModelStateOperation() {}
     QmlPropertyChanges(const ModelNode &modelNode) : QmlModelStateOperation(modelNode) {}
     bool isValid() const;
+    static bool isValidQmlPropertyChanges(const ModelNode &modelNode);
     void removeProperty(const PropertyName &name);
 };
 

src/plugins/qmldesigner/designercore/model/qmlchangeset.cpp

@@ -50,7 +50,12 @@ void QmlModelStateOperation::setTarget(const ModelNode &target)
 
 bool QmlPropertyChanges::isValid() const
 {
-    return QmlModelNodeFacade::isValid() && modelNode().metaInfo().isSubclassOf("QtQuick.PropertyChanges", -1, -1);
+    return isValidQmlPropertyChanges(modelNode());
+}
+
+bool QmlPropertyChanges::isValidQmlPropertyChanges(const ModelNode &modelNode)
+{
+    return isValidQmlModelNodeFacade(modelNode) && modelNode.metaInfo().isSubclassOf("QtQuick.PropertyChanges", -1, -1);
 }
 
 bool QmlModelStateOperation::isValid() const