QmlDesigner: Add allTimelines

This makes it easy to retrieve all existing timelines.

Change-Id: I61fdacce28ea7c8afe48da81b87c8b47ee1cec26
Reviewed-by: Henning Gründl <henning.gruendl@qt.io>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

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

@@ -138,6 +138,8 @@ public:
 
     QmlModelStateGroup states() const;
 
+    QList<ModelNode> allTimelines() const;
+
 protected:
     NodeInstance nodeInstance() const;
     QmlObjectNode nodeForInstance(const NodeInstance &instance) const;

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

@@ -590,6 +590,18 @@ QmlModelStateGroup QmlObjectNode::states() const
         return QmlModelStateGroup();
 }
 
+QList<ModelNode> QmlObjectNode::allTimelines() const
+{
+    QList<ModelNode> timelineNodes;
+    const auto allNodes = view()->allModelNodes();
+    for (const auto &timelineNode : allNodes) {
+        if (QmlTimeline::isValidQmlTimeline(timelineNode))
+            timelineNodes.append(timelineNode);
+    }
+
+    return timelineNodes;
+}
+
 /*!
     Removes a variant property of the object specified by \a name from the
     model.