macOS: Tie QCocoaWindowManager lifetime to QCocoaIntegration

To avoid any static initialization fiasco when Qt is being used
in a plugin.

Fixes: QTBUG-101150
Pick-to: 6.2 6.3
Change-Id: I68fa03f982d0c07e4b725ed5f4a1f738e0220438
Reviewed-by: <stefan.wastl@native-instruments.de>
Reviewed-by: Doris Verria <doris.verria@qt.io>
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

src/plugins/platforms/cocoa/qcocoaintegration.h

@@ -51,6 +51,7 @@
 #if QT_CONFIG(vulkan)
 #include "qcocoavulkaninstance.h"
 #endif
+#include "qcocoawindowmanager.h"
 
 #include <QtCore/QScopedPointer>
 #include <qpa/qplatformintegration.h>
@@ -155,6 +156,8 @@ private:
     mutable QCocoaVulkanInstance *mCocoaVulkanInstance = nullptr;
 #endif
     QHash<QWindow *, NSToolbar *> mToolbars;
+
+    QCocoaWindowManager m_windowManager;
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(QCocoaIntegration::Options)

src/plugins/platforms/cocoa/qcocoaintegration.mm

@@ -82,11 +82,6 @@ QT_BEGIN_NAMESPACE
 
 Q_LOGGING_CATEGORY(lcQpa, "qt.qpa", QtWarningMsg);
 
-// Lives here so that the linker is forced to include the QCocoaWindowManager
-// object file also in static builds.
-static void initializeWindowManager() { Q_UNUSED(QCocoaWindowManager::instance()); }
-Q_CONSTRUCTOR_FUNCTION(initializeWindowManager)
-
 static void logVersionInformation()
 {
     if (!lcQpa().isInfoEnabled())

src/plugins/platforms/cocoa/qcocoawindowmanager.h

@@ -41,18 +41,21 @@
 #define QCOCOAWINDOWMANAGER_H
 
 #include <QtCore/qglobal.h>
+#include <QtCore/private/qcore_mac_p.h>
 
 QT_BEGIN_NAMESPACE
 
 class QCocoaWindowManager
 {
 public:
-    static QCocoaWindowManager *instance();
+    QCocoaWindowManager();
 
 private:
-    QCocoaWindowManager();
+
+    QMacNotificationObserver m_applicationDidFinishLaunchingObserver;
     void initialize();
 
+    QMacKeyValueObserver m_modalSessionObserver;
     void modalSessionChanged();
 };
 

src/plugins/platforms/cocoa/qcocoawindowmanager.mm

@@ -49,19 +49,13 @@
 
 QT_BEGIN_NAMESPACE
 
-QCocoaWindowManager *QCocoaWindowManager::instance()
-{
-    static auto *instance = new QCocoaWindowManager;
-    return instance;
-}
-
 QCocoaWindowManager::QCocoaWindowManager()
 {
     if (NSApp) {
         initialize();
     } else {
-        static auto applicationDidFinishLaunching(QMacNotificationObserver(nil,
-            NSApplicationDidFinishLaunchingNotification, [this] { initialize(); }));
+        m_applicationDidFinishLaunchingObserver = QMacNotificationObserver(nil,
+            NSApplicationDidFinishLaunchingNotification, [this] { initialize(); });
     }
 }
 
@@ -74,9 +68,9 @@ void QCocoaWindowManager::initialize()
     // event dispatcher sessions allows us to track session started by native
     // APIs as well. We need to check the initial state as well, in case there
     // is already a modal session running.
-    static auto modalSessionObserver(QMacKeyValueObserver(
+    m_modalSessionObserver = QMacKeyValueObserver(
         NSApp, @"modalWindow", [this] { modalSessionChanged(); },
-        NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew));
+        NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew);
 }
 
 void QCocoaWindowManager::modalSessionChanged()