Fix QQmlDelegateModel ignoring layoutChange in certain situations

Fix a regression introduced by commit a0aefe1 which caused the model to
ignore layout changes if d->m_adaptorModel.rootIndex was just a descendant
of any of the parent indexes, or when no parent indexes at all were provided
in the notification.

Task-number: QTBUG-39492
Change-Id: I4c97929d25ef75947ccfcbbe5bc234096689c58d
Reviewed-by: Alan Alpert <aalpert@blackberry.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/tests/auto/quick/qquicklistview/data/qtbug39492.qml b/tests/auto/quick/qquicklistview/data/qtbug39492.qml
new file mode 100644
index 0000000000..4df3a080d7
--- /dev/null
+++ b/tests/auto/quick/qquicklistview/data/qtbug39492.qml
@@ -0,0 +1,40 @@
+import QtQuick 2.0
+import QtQml.Models 2.1
+
+Rectangle {
+    id: root
+    width: 240
+    height: 320
+    color: "#ffffff"
+
+
+    Component {
+        id: myDelegate
+        Rectangle {
+            id: wrapper
+            objectName: "wrapper"
+            height: 20
+            width: 240
+            Text {
+                objectName: "delegateText"
+                text: display
+            }
+            color: ListView.isCurrentItem ? "lightsteelblue" : "white"
+        }
+    }
+
+    DelegateModel {
+        id: delegateModel
+        objectName: "delegateModel"
+        model: testModel
+        delegate: myDelegate
+    }
+
+    ListView {
+        id: list
+        objectName: "listView"
+        model: delegateModel;
+        focus: true
+        anchors.fill: parent
+    }
+}