Fix namespaced build of demobrowser

Change-Id: I6f863676dabacbe193e148481178753f05bd2869
Reviewed-by: Michal Klocek <michal.klocek@theqtcompany.com>
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@theqtcompany.com>

examples/webenginewidgets/demobrowser/fullscreennotification.h

@@ -44,9 +44,11 @@
 
 #include <QWidget>
 
+QT_BEGIN_NAMESPACE
 class QLabel;
 class QGridLayout;
 class QPropertyAnimation;
+QT_END_NAMESPACE
 
 class FullScreenNotification : public QWidget
 {
@@ -72,5 +74,4 @@ private:
     int y;
 };
 
-
 #endif // FULLSCREENNOTIFICATION_H

examples/webenginewidgets/demobrowser/tabwidget.h

@@ -128,13 +128,16 @@ private:
 
 #include <QtCore/QUrl>
 #include <QtWidgets/QTabWidget>
-QT_BEGIN_NAMESPACE
+
 class FullScreenNotification;
+
+QT_BEGIN_NAMESPACE
 class QCompleter;
 class QLineEdit;
 class QMenu;
 class QStackedWidget;
 QT_END_NAMESPACE
+
 /*!
     TabWidget that contains WebViews and a stack widget of associated line edits.