QPI/Cocoa: QNSView - guard removeFromSuperview by autorelease pool

removeFromSuperview could be called from outside the Qt domain (e.g from
a native cocoa gui). we need to guard it by an autorelease pool to make
sure that potential release/dealloc methods are not postponed to a point
when we do not have a qapplication anymore

Change-Id: If65cce4c524a16ffee125694c534f900c7d08fa8
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@theqtcompany.com>

src/plugins/platforms/cocoa/qnsview.h

@@ -99,6 +99,7 @@ Q_FORWARD_DECLARE_OBJC_CLASS(QT_MANGLE_NAMESPACE(QNSViewMouseMoveHelper));
 - (void)textInputContextKeyboardSelectionDidChangeNotification : (NSNotification *) textInputContextKeyboardSelectionDidChangeNotification;
 - (void)viewDidHide;
 - (void)viewDidUnhide;
+- (void)removeFromSuperview;
 
 - (BOOL)isFlipped;
 - (BOOL)acceptsFirstResponder;

src/plugins/platforms/cocoa/qnsview.mm

@@ -498,6 +498,12 @@ QT_WARNING_POP
     m_platformWindow->exposeWindow();
 }
 
+- (void)removeFromSuperview
+{
+    QMacAutoReleasePool pool;
+    [super removeFromSuperview];
+}
+
 - (void) flushBackingStore:(QCocoaBackingStore *)backingStore region:(const QRegion &)region offset:(QPoint)offset
 {
     m_backingStore = backingStore;