Provide QPlatformWindow::hasPendingUpdateRequest() helper function

So that platform plugins don't need to dive into QWindowPrivate.

Change-Id: Ia2d94b3e9236e4a68857e6afe7af063f1b0d0aeb
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

src/gui/kernel/qplatformwindow.cpp

@@ -748,6 +748,16 @@ void QPlatformWindow::requestUpdate()
     wp->updateTimer = w->startTimer(timeout, Qt::PreciseTimer);
 }
 
+/*!
+    Returns true if the window has a pending update request.
+
+    \sa requestUpdate(), deliverUpdateRequest()
+*/
+bool QPlatformWindow::hasPendingUpdateRequest() const
+{
+    return qt_window_private(window())->updateRequestPending;
+}
+
 /*!
     Delivers an QEvent::UpdateRequest event to the window.
 
@@ -757,6 +767,8 @@ void QPlatformWindow::requestUpdate()
 */
 void QPlatformWindow::deliverUpdateRequest()
 {
+    Q_ASSERT(hasPendingUpdateRequest());
+
     QWindow *w = window();
     QWindowPrivate *wp = qt_window_private(w);
     wp->updateRequestPending = false;

src/gui/kernel/qplatformwindow.h

@@ -144,6 +144,7 @@ public:
         const QRect &initialGeometry, int defaultWidth, int defaultHeight);
 
     virtual void requestUpdate();
+    bool hasPendingUpdateRequest() const;
     virtual void deliverUpdateRequest();
 
     // Window property accessors. Platform plugins should use these

src/plugins/platforms/cocoa/qnsview_drawing.mm

@@ -115,17 +115,15 @@
     }
 #endif
 
-    QWindowPrivate *windowPrivate = qt_window_private(m_platformWindow->window());
-
     if (m_updateRequested) {
-        Q_ASSERT(windowPrivate->updateRequestPending);
+        Q_ASSERT(m_platformWindow->hasPendingUpdateRequest());
         m_platformWindow->deliverUpdateRequest();
         m_updateRequested = false;
     } else {
         m_platformWindow->handleExposeEvent(dirtyRegion);
     }
 
-    if (windowPrivate->updateRequestPending) {
+    if (m_platformWindow->hasPendingUpdateRequest()) {
         // A call to QWindow::requestUpdate was issued during event delivery above,
         // but AppKit will reset the needsDisplay state of the view after completing
         // the current display cycle, so we need to defer the request to redisplay.

src/plugins/platforms/ios/qiosscreen.mm

@@ -394,18 +394,17 @@ void QIOSScreen::deliverUpdateRequests() const
         if (platformScreenForWindow(window) != this)
             continue;
 
-        QWindowPrivate *wp = qt_window_private(window);
-        if (!wp->updateRequestPending)
-            continue;
-
         QPlatformWindow *platformWindow = window->handle();
         if (!platformWindow)
             continue;
 
+        if (!platformWindow->hasPendingUpdateRequest())
+            continue;
+
         platformWindow->deliverUpdateRequest();
 
         // Another update request was triggered, keep the display link running
-        if (wp->updateRequestPending)
+        if (platformWindow->hasPendingUpdateRequest())
             pauseUpdates = false;
     }