QML: Change C++ benchmark to reflect QML benchmark

The QQmlListReference will build a property cache entry, but it won't
assign it to an engine when none is available (meaning: it would create
the entry every time a QQmlListReference is created). QML won't do that,
because it (obviously) has an engine available.

Change-Id: I46eeaf3dffcb690902dd3d78be48c8509be6e84d
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 2 insertions, 1 deletions

diff --git a/tests/benchmarks/qml/creation/tst_creation.cpp b/tests/benchmarks/qml/creation/tst_creation.cpp
index dbda07be5a..6c8d1eb21a 100644
--- a/tests/benchmarks/qml/creation/tst_creation.cpp
+++ b/tests/benchmarks/qml/creation/tst_creation.cpp
@@ -256,12 +256,13 @@ void tst_creation::itemtree_cpp()
 
 void tst_creation::itemtree_data_cpp()
 {
+    QQmlEngine engine;
     QBENCHMARK {
         QQuickItem *item = new QQuickItem;
         for (int i = 0; i < 30; ++i) {
             QQuickItem *child = new QQuickItem;
             QQmlGraphics_setParent_noEvent(child,item);
-            QQmlListReference ref(item, "data");
+            QQmlListReference ref(item, "data", &engine);
             ref.append(child);
         }
         delete item;