Fix crash in QRuntimeGraphicsSystem due to destruction order.

Firstly, fix a "leak" by deleting the graphics system when QApplication
is destroyed.

Secondly, fix a crash when the following scenario occurs:
- ~QApplication() deletes the current graphics system (see above)
- ~QApplication() calls qt_cleanup()
- qt_cleanup() calls QPixmapCache::clear() to delete pixmaps
- ~QRuntimePixmapData() tries to remove the pixmap from the runtime
  graphics system, but it has already been deleted.
- *Crash*

Reviewed-by: Gunnar Sletta
Reviewed-by: Jani Hautakangas

1 files changed, 2 insertions, 0 deletions

diff --git a/src/gui/kernel/qapplication.cpp b/src/gui/kernel/qapplication.cpp
index 82dd83a..ebad56e 100644
--- a/src/gui/kernel/qapplication.cpp
+++ b/src/gui/kernel/qapplication.cpp
@@ -1116,6 +1116,8 @@ QApplication::~QApplication()
     QApplicationPrivate::app_style = 0;
     delete QApplicationPrivate::app_icon;
     QApplicationPrivate::app_icon = 0;
+    delete QApplicationPrivate::graphics_system;
+    QApplicationPrivate::graphics_system = 0;
 #ifndef QT_NO_CURSOR
     d->cursor_list.clear();
 #endif