QmlDesigner: Keep Qt 3D scenes from crashing

If we do not set the source property of the Q3DSPresentationItem
nothing is actually rendered.

If a scene is rendered in the puppet we get an invalid OpenGL context
when rendering in the qml2puppet.

Change-Id: I74db0df7de759e830499967bc6985745be291856
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

share/qtcreator/qml/qmlpuppet/qml2puppet/instances/qt3dpresentationnodeinstance.cpp

@@ -0,0 +1,51 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#include "qt3presentationdnodeinstance.h"
+#include <QQuickItem>
+
+namespace QmlDesigner {
+namespace Internal {
+
+Qt3DPresentationNodeInstance::Qt3DPresentationNodeInstance(QObject *object)
+    : ObjectNodeInstance(object)
+{
+}
+
+Qt3DPresentationNodeInstance::Pointer Qt3DPresentationNodeInstance::create(QObject *object)
+{
+    Pointer instance(new Qt3DPresentationNodeInstance(object));
+    instance->populateResetHashes();
+
+    return instance;
+}
+
+PropertyNameList Qt3DPresentationNodeInstance::ignoredProperties() const
+{
+    static const PropertyNameList properties({"source"});
+    return properties;
+}
+} // namespace Internal
+} // namespace QmlDesigner