Add Window.window attached property

The Window attached property exposes all kinds of window attributes,
but not the window itself. Being able to access the window is often
useful for various purposes. For example, in QML TestCase, to be able
to access the window of the TestCase so that one can call various
slots such as requestActivate().

Change-Id: Id03c9f277bb17810b41a60957011ccf07399e149
Reviewed-by: Mitch Curtis <mitch.curtis@theqtcompany.com>

src/quick/items/qquickwindow.cpp

@@ -3871,6 +3871,14 @@ void QQuickWindow::resetOpenGLState()
     that you set if the requested flags could not be fulfilled.
  */
 
+/*!
+    \qmlattachedproperty Window Window::window
+    \since 5.7
+
+    This attached property holds the item's window.
+    The Window attached property can be attached to any Item.
+*/
+
 /*!
     \qmlattachedproperty int Window::width
     \qmlattachedproperty int Window::height

src/quick/items/qquickwindowattached.cpp

@@ -51,9 +51,9 @@ QQuickWindowAttached::QQuickWindowAttached(QObject* attachee)
 {
     m_attachee = qobject_cast<QQuickItem*>(attachee);
     if (m_attachee && m_attachee->window()) // It might not be in a window yet
-        windowChanged(m_attachee->window());
+        windowChange(m_attachee->window());
     if (m_attachee)
-        connect(m_attachee, &QQuickItem::windowChanged, this, &QQuickWindowAttached::windowChanged);
+        connect(m_attachee, &QQuickItem::windowChanged, this, &QQuickWindowAttached::windowChange);
 }
 
 QWindow::Visibility QQuickWindowAttached::visibility() const
@@ -86,7 +86,12 @@ int QQuickWindowAttached::height() const
     return (m_window ? m_window->height() : 0);
 }
 
-void QQuickWindowAttached::windowChanged(QQuickWindow *window)
+QQuickWindow *QQuickWindowAttached::window() const
+{
+    return m_window;
+}
+
+void QQuickWindowAttached::windowChange(QQuickWindow *window)
 {
     if (window != m_window) {
         QQuickWindow* oldWindow = m_window;
@@ -95,6 +100,8 @@ void QQuickWindowAttached::windowChanged(QQuickWindow *window)
         if (oldWindow)
             oldWindow->disconnect(this);
 
+        emit windowChanged();
+
         if (!oldWindow || !window || window->visibility() != oldWindow->visibility())
             emit visibilityChanged();
         if (!oldWindow || !window || window->isActive() != oldWindow->isActive())

src/quick/items/qquickwindowattached_p.h

@@ -69,6 +69,7 @@ class Q_AUTOTEST_EXPORT QQuickWindowAttached : public QObject
     Q_PROPERTY(QQuickItem* contentItem READ contentItem NOTIFY contentItemChanged)
     Q_PROPERTY(int width READ width NOTIFY widthChanged)
     Q_PROPERTY(int height READ height NOTIFY heightChanged)
+    Q_PROPERTY(QQuickWindow *window READ window NOTIFY windowChanged)
 
 public:
     QQuickWindowAttached(QObject* attachee);
@@ -79,6 +80,7 @@ public:
     QQuickItem* contentItem() const;
     int width() const;
     int height() const;
+    QQuickWindow *window() const;
 
 Q_SIGNALS:
 
@@ -88,9 +90,10 @@ Q_SIGNALS:
     void contentItemChanged();
     void widthChanged();
     void heightChanged();
+    void windowChanged();
 
 protected Q_SLOTS:
-    void windowChanged(QQuickWindow*);
+    void windowChange(QQuickWindow*);
 
 private:
     QQuickWindow* m_window;

tests/auto/quick/qquickwindow/data/windowattached.qml

@@ -9,6 +9,7 @@ Rectangle {
     property Item contentItem: root.Window.contentItem
     property int windowWidth: root.Window.width
     property int windowHeight: root.Window.height
+    property var window: root.Window.window
     Text {
         objectName: "rectangleWindowText"
         anchors.centerIn: parent
@@ -26,6 +27,7 @@ Rectangle {
             property Item contentItem: Window.contentItem
             property int windowWidth: Window.width
             property int windowHeight: Window.height
+            property var window: Window.window
         }
     }
 }

tests/auto/quick/qquickwindow/tst_qquickwindow.cpp

@@ -2033,6 +2033,7 @@ void tst_qquickwindow::attachedProperty()
     QCOMPARE(view.rootObject()->property("contentItem").value<QQuickItem*>(), view.contentItem());
     QCOMPARE(view.rootObject()->property("windowWidth").toInt(), view.width());
     QCOMPARE(view.rootObject()->property("windowHeight").toInt(), view.height());
+    QCOMPARE(view.rootObject()->property("window").value<QQuickView*>(), &view);
 
     QQuickWindow *innerWindow = view.rootObject()->findChild<QQuickWindow*>("extraWindow");
     QVERIFY(innerWindow);
@@ -2045,11 +2046,13 @@ void tst_qquickwindow::attachedProperty()
     QCOMPARE(text->property("contentItem").value<QQuickItem*>(), innerWindow->contentItem());
     QCOMPARE(text->property("windowWidth").toInt(), innerWindow->width());
     QCOMPARE(text->property("windowHeight").toInt(), innerWindow->height());
+    QCOMPARE(text->property("window").value<QQuickWindow*>(), innerWindow);
 
     text->setParentItem(0);
     QVERIFY(!text->property("contentItem").value<QQuickItem*>());
     QCOMPARE(text->property("windowWidth").toInt(), 0);
     QCOMPARE(text->property("windowHeight").toInt(), 0);
+    QVERIFY(!text->property("window").value<QQuickWindow*>());
 }
 
 class RenderJob : public QRunnable