macOS: Handle platform window destroy and create in backingstore

We observe changes to the NSWindow to pick up color space changes,
so we need to track when the platform window is destroyed and created
to match our observer with the recreated NSWindow.

This does not handle the fact that we're internally recreating the
NSWindow if certain window flag changes requires so, without letting
clients know via surface events.

Task-number: QTBUG-85915
Pick-to: 5.15
Change-Id: I7a7d728c742def79adebaadc985cedd86ea0d581
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoabackingstore.h b/src/plugins/platforms/cocoa/qcocoabackingstore.h
index c29ab2d8f8..4a5b3886f2 100644
--- a/src/plugins/platforms/cocoa/qcocoabackingstore.h
+++ b/src/plugins/platforms/cocoa/qcocoabackingstore.h
@@ -96,6 +96,9 @@ public:
     QPlatformGraphicsBuffer *graphicsBuffer() const override;
 
 private:
+    void observeBackingPropertiesChanges();
+    bool eventFilter(QObject *watched, QEvent *event) override;
+
     QSize m_requestedSize;
     QRegion m_paintedRegion;