Turn fullScreenRequest into a well-behaved value type

Add a default constructor so that QMetaType can create it.

Task-number: QTBUG-108649
Task-number: QTBUG-135032
Pick-to: 6.9 6.8
Change-Id: If82aa9e318f17ba5727b3bd6ad3684afb8b36c7f
Reviewed-by: Michal Klocek <[email protected]>

Author: Ulf Hermann

src/core/api/qwebenginefullscreenrequest.h

@@ -23,6 +23,7 @@ class Q_WEBENGINECORE_EXPORT QWebEngineFullScreenRequest
     Q_PROPERTY(QUrl origin READ origin CONSTANT)
 
 public:
+    QWebEngineFullScreenRequest() : QWebEngineFullScreenRequest(QUrl(), false, [](bool){}) {}
     QWebEngineFullScreenRequest(const QWebEngineFullScreenRequest &other);
     QWebEngineFullScreenRequest &operator=(const QWebEngineFullScreenRequest &other);
     QWebEngineFullScreenRequest(QWebEngineFullScreenRequest &&other);