Cocoa: Fix shadowless popups

The window shadow was never invalidated after setting the transparency
mask. We now do it right after the first draw after setting the mask.

Change-Id: Icc5c6002d25abeb25d58ee4d1f868e928121ae9b
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>

src/plugins/platforms/cocoa/qnsview.h

@@ -59,6 +59,7 @@ QT_END_NAMESPACE
     QPoint m_backingStoreOffset;
     CGImageRef m_maskImage;
     uchar *m_maskData;
+    bool m_shouldInvalidateWindowShadow;
     QWindow *m_window;
     QCocoaWindow *m_platformWindow;
     Qt::MouseButtons m_buttons;
@@ -76,6 +77,7 @@ QT_END_NAMESPACE
 - (void)setQCocoaGLContext:(QCocoaGLContext *)context;
 - (void)flushBackingStore:(QCocoaBackingStore *)backingStore region:(const QRegion &)region offset:(QPoint)offset;
 - (void)setMaskRegion:(const QRegion *)region;
+- (void)invalidateWindowShadowIfNeeded;
 - (void)drawRect:(NSRect)dirtyRect;
 - (void)updateGeometry;
 - (void)windowNotification : (NSNotification *) windowNotification;

src/plugins/platforms/cocoa/qnsview.mm

@@ -80,6 +80,7 @@ static QTouchDevice *touchDevice = 0;
         m_backingStore = 0;
         m_maskImage = 0;
         m_maskData = 0;
+        m_shouldInvalidateWindowShadow = false;
         m_window = 0;
         m_buttons = Qt::NoButton;
         m_sendKeyEvent = false;
@@ -266,6 +267,7 @@ static QTouchDevice *touchDevice = 0;
 
 - (void) setMaskRegion:(const QRegion *)region
 {
+    m_shouldInvalidateWindowShadow = true;
     if (m_maskImage)
         CGImageRelease(m_maskImage);
     if (region->isEmpty()) {
@@ -285,6 +287,14 @@ static QTouchDevice *touchDevice = 0;
     m_maskImage = qt_mac_toCGImage(maskImage, true, &m_maskData);
 }
 
+- (void)invalidateWindowShadowIfNeeded
+{
+    if (m_shouldInvalidateWindowShadow && m_platformWindow->m_nsWindow) {
+        [m_platformWindow->m_nsWindow invalidateShadow];
+        m_shouldInvalidateWindowShadow = false;
+    }
+}
+
 - (void) drawRect:(NSRect)dirtyRect
 {
     if (!m_backingStore)
@@ -334,6 +344,8 @@ static QTouchDevice *touchDevice = 0;
     CGContextRestoreGState(cgContext);
     CGImageRelease(cleanImg);
     CGImageRelease(subMask);
+
+    [self invalidateWindowShadowIfNeeded];
 }
 
 - (BOOL) isFlipped