Let C++ create and own the QMLBridge instance

It's a global singleton type, doesn't make sense to let QML manage it.
Before this change, it was destroyed too early, causing warnings on exit like:

TypeError: Cannot read property 'myData' of null

Author: Vogtinator

main.cpp

@@ -109,8 +109,13 @@ int main(int argc, char **argv)
 
     migrateSettings();
 
+    QMLBridge qmlBridge;
+    QQmlEngine::setObjectOwnership(&qmlBridge, QQmlEngine::CppOwnership);
+
     // Register QMLBridge for Keypad<->Emu communication
-    qmlRegisterSingletonType<QMLBridge>("Firebird.Emu", 1, 0, "Emu", qmlBridgeFactory);
+    qmlRegisterSingletonType<QMLBridge>("Firebird.Emu", 1, 0, "Emu", [](QQmlEngine *, QJSEngine *) -> QObject* {
+        return the_qml_bridge;
+    });
     // Register QtFramebuffer for QML display
     qmlRegisterType<QMLFramebuffer>("Firebird.Emu", 1, 0, "EmuScreen");
     // Register KitModel

qmlbridge.cpp

@@ -687,14 +687,6 @@ void QMLBridge::notifyButtonStateChanged(int row, int col, bool state)
     emit buttonStateChanged(col + row * KEYPAD_COLS, state);
 }
 
-QObject *qmlBridgeFactory(QQmlEngine *engine, QJSEngine *scriptEngine)
-{
-    Q_UNUSED(engine)
-    Q_UNUSED(scriptEngine)
-
-    return new QMLBridge();
-}
-
 void QMLBridge::touchpadStateChanged()
 {
     touchpadStateChanged(float(keypad.touchpad_x)/TOUCHPAD_X_MAX, 1.0f-(float(keypad.touchpad_y)/TOUCHPAD_Y_MAX), keypad.touchpad_contact, keypad.touchpad_down);

qmlbridge.h

@@ -180,7 +180,4 @@ public slots:
 
 extern QMLBridge *the_qml_bridge;
 
-QObject *qmlBridgeFactory(QQmlEngine *engine, QJSEngine *scriptEngine);
-
-
 #endif // QMLBRIDGE_H