Cocoa: Fix qmlscene flicker on startup.

The SG render thread was racing window creation in
the GUI thread, which would cause flicker if the
window won the race and was shown before the SG
thread had a frame ready.

Send a synchronous expose event before showing the
window - this will wait for the SG render thread.

In addition, don't defer NSwindow creation. The GL
context setup is done before the window is shown
and needs a fully created window.

New API: QWindowSystemInterface::handleSynchronousExposeEvent
Retire: QWindowSystemInterface::handleExposeEvent

Change-Id: I0bb46089d16ec4882aaac8db67b57d15e0f51531
Reviewed-on: http://codereview.qt.nokia.com/3399
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@nokia.com>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@nokia.com>

2 files changed, 3 insertions, 3 deletions

diff --git a/src/gui/kernel/qwindowsysteminterface_qpa.cpp b/src/gui/kernel/qwindowsysteminterface_qpa.cpp
index d6f94b6261..d862d05baa 100644
--- a/src/gui/kernel/qwindowsysteminterface_qpa.cpp
+++ b/src/gui/kernel/qwindowsysteminterface_qpa.cpp
@@ -276,10 +276,10 @@ void QWindowSystemInterface::handleUnmapEvent(QWindow *tlw)
     QWindowSystemInterfacePrivate::queueWindowSystemEvent(e);
 }
 
-void QWindowSystemInterface::handleExposeEvent(QWindow *tlw, const QRegion &region)
+void QWindowSystemInterface::handleSynchronousExposeEvent(QWindow *tlw, const QRegion &region)
 {
     QWindowSystemInterfacePrivate::ExposeEvent *e = new QWindowSystemInterfacePrivate::ExposeEvent(tlw, region);
-    QWindowSystemInterfacePrivate::queueWindowSystemEvent(e);
+    QGuiApplicationPrivate::processWindowSystemEvent(e); // send event immediately.
 }
 
 bool QWindowSystemInterface::sendWindowSystemEvents(QAbstractEventDispatcher *eventDispatcher, QEventLoop::ProcessEventsFlags flags)
diff --git a/src/gui/kernel/qwindowsysteminterface_qpa.h b/src/gui/kernel/qwindowsysteminterface_qpa.h
index 2f3f8a171e..99db5f2b17 100644
--- a/src/gui/kernel/qwindowsysteminterface_qpa.h
+++ b/src/gui/kernel/qwindowsysteminterface_qpa.h
@@ -105,7 +105,7 @@ public:
     static void handleMapEvent(QWindow *w);
     static void handleUnmapEvent(QWindow *w);
 
-    static void handleExposeEvent(QWindow *w, const QRegion &region);
+    static void handleSynchronousExposeEvent(QWindow *tlw, const QRegion &region);
 
     // Drag and drop. These events are sent immediately.
     static Qt::DropAction handleDrag(QWindow *w, QMimeData *dropData, const QPoint &p);