Gui: [skip ci] add sub-classes of the MDIView to the type system

src/Mod/Web/Gui/AppWebGui.cpp

@@ -170,6 +170,7 @@ PyMOD_INIT_FUNC(WebGui)
 
     // instantiating the commands
     CreateWebCommands();
+    WebGui::BrowserView::init();
     WebGui::Workbench::init();
 
      // add resources and reloads the translators

src/Mod/Web/Gui/BrowserView.cpp

@@ -359,6 +359,8 @@ void WebView::triggerContextMenuAction(int id)
 
 /* TRANSLATOR Gui::BrowserView */
 
+TYPESYSTEM_SOURCE_ABSTRACT(WebGui::BrowserView, Gui::MDIView)
+
 /**
  *  Constructs a BrowserView which is a child of 'parent', with the
  *  name 'name'.

src/Mod/Web/Gui/BrowserView.h

@@ -33,7 +33,7 @@
 #include <QWebEngineView>
 namespace WebGui {
 class WebEngineUrlRequestInterceptor;
-};
+}
 #elif defined(QTWEBKIT)
 #include <QWebView>
 #endif
@@ -79,6 +79,8 @@ class WebGuiExport BrowserView : public Gui::MDIView,
 {
     Q_OBJECT
 
+    TYPESYSTEM_HEADER();
+
 public:
     BrowserView(QWidget* parent);
     ~BrowserView();