qtquick: Fix Stack creating two TabBar's

It's created by the controller, we shouldn't create another one
in the view

src/qtquick/views/Stack_qtquick.cpp

@@ -41,7 +41,6 @@ Stack_qtquick::Stack_qtquick(Controllers::Stack *controller,
 
 void Stack_qtquick::init()
 {
-    m_tabBar = new Controllers::TabBar(m_stack);
     Q_EMIT tabBarChanged();
 }
 
@@ -89,7 +88,7 @@ void Stack_qtquick::setCurrentDockWidget(int index)
 
 QObject *Stack_qtquick::tabBarViewObj() const
 {
-    return m_tabBar->view()->asQObject();
+    return m_stack->tabBar()->view()->asQObject();
 }
 
 Controllers::DockWidget *Stack_qtquick::currentDockWidget() const

src/qtquick/views/Stack_qtquick.h

@@ -80,7 +80,6 @@ protected:
 private:
     Q_DISABLE_COPY(Stack_qtquick)
     DockWidgetModel *const m_dockWidgetModel;
-    Controllers::TabBar *m_tabBar = nullptr;
     Controllers::Stack *const m_stack;
     Controllers::DockWidget *m_currentDockWidget = nullptr;
 };

src/qtquick/views/TabBar_qtquick.cpp

@@ -34,8 +34,10 @@ TabBar_qtquick::TabBar_qtquick(Controllers::TabBar *controller, QQuickItem *pare
 
 QHash<int, QQuickItem *> TabBar_qtquick::qmlTabs() const
 {
-    if (!m_tabBarQmlItem)
+    if (!m_tabBarQmlItem) {
+        qWarning() << Q_FUNC_INFO << "No visual tab bar item yet" << this;
         return {};
+    }
 
     /// Returns the list of QtQuickControls tabs in our tab bar
     QHash<int, QQuickItem *> tabs;
@@ -50,6 +52,8 @@ QHash<int, QQuickItem *> TabBar_qtquick::qmlTabs() const
                     tabs.insert(index, item);
             }
         }
+    } else {
+        qWarning() << Q_FUNC_INFO << "Couldn't find the internal ListView";
     }
 
     return tabs;
@@ -130,23 +134,17 @@ bool TabBar_qtquick::event(QEvent *ev)
 
 QQuickItem *TabBar_qtquick::tabAt(int index) const
 {
-    QQuickItem *view = listView();
-    if (!view)
-        return nullptr;
-
-    QQuickItem *item = nullptr;
-    QMetaObject::invokeMethod(view, "itemAtIndex", Q_RETURN_ARG(QQuickItem *, item),
-                              Q_ARG(int, index));
-
-    return item;
+    const QHash<int, QQuickItem *> tabs = qmlTabs();
+    return tabs.value(index, nullptr);
 }
 
 QQuickItem *TabBar_qtquick::listView() const
 {
     // Returns the internal ListView of the TabBar
-
-    if (!m_tabBarQmlItem)
+    if (!m_tabBarQmlItem) {
+        qWarning() << Q_FUNC_INFO << "No visual tab bar item yet";
         return nullptr;
+    }
 
     const QList<QQuickItem *> children = m_tabBarQmlItem->childItems();
     for (QQuickItem *child : children) {