Remove usage of private call QWidgetPrivate::updateWidgetTransform()

It used to be needed in 5.6 for IME window placement purposes, but
since 5.7 when we switched to using QQuickWidget instead of
QOpenGLWidget as a result of commit
800365f6

, the updateWidgetTransform
gets called implicitly because we forward FocusIn events to
QQuickWidget::event, which forwards them to QWidget::event which
calls updateWidgetTransform for us.

Task-number: QTBUG-63098
Change-Id: I0a0ba50c1491797b37765d26d761c358c156950f
Reviewed-by: Michael Brüning <michael.bruning@qt.io>

src/webenginewidgets/render_widget_host_view_qt_delegate_widget.cpp

@@ -51,8 +51,6 @@
 #include <QWindow>
 #include <private/qquickwindow_p.h>
 
-#include <private/qwidget_p.h>
-
 namespace QtWebEngineCore {
 
 class RenderWidgetHostViewQuickItem : public QQuickItem {
@@ -462,12 +460,6 @@ bool RenderWidgetHostViewQtDelegateWidget::event(QEvent *event)
         break;
     }
 
-    QEvent::Type type = event->type();
-    if (type == QEvent::FocusIn) {
-        QWidgetPrivate *d = QWidgetPrivate::get(this);
-        d->updateWidgetTransform(event);
-    }
-
     if (event->type() == QEvent::MouseButtonDblClick) {
         // QWidget keeps the Qt4 behavior where the DblClick event would replace the Press event.
         // QtQuick is different by sending both the Press and DblClick events for the second press