Dialogs: don't create platform helpers unconditionally

No matter if Qt::AA_DontUseNativeDialogs was set, both QFileDialog and
QColorDialog were always unconditionally creating the platform helper
at construction time:

    QFooDialog()
    -> QFooDialogPrivate::init()
    -> QFooDialogPrivate::platformFooHelper()
    -> QDialogPrivate::platformHelper()

Only QFontDialog had the platformHelper() calls guarded with
canBeNativeDialog(). => Move the canBeNativeDialog() check inside
QDialogPrivate::platformHelper() where the platform helper
instance is created.

Task-number: QTBUG-55276
Change-Id: I84b595fbd009c70a3a1976ddbb32a835270c5203
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

1 files changed, 4 insertions, 8 deletions

diff --git a/src/widgets/dialogs/qfontdialog.cpp b/src/widgets/dialogs/qfontdialog.cpp
index 2a500d3a08..c373bcf1df 100644
--- a/src/widgets/dialogs/qfontdialog.cpp
+++ b/src/widgets/dialogs/qfontdialog.cpp
@@ -824,10 +824,8 @@ void QFontDialog::setCurrentFont(const QFont &font)
     d->strikeout->setChecked(font.strikeOut());
     d->underline->setChecked(font.underline());
     d->updateFamilies();
-    if (d->canBeNativeDialog()) {
-        if (QPlatformFontDialogHelper *helper = d->platformFontDialogHelper())
-            helper->setCurrentFont(font);
-    }
+    if (QPlatformFontDialogHelper *helper = d->platformFontDialogHelper())
+        helper->setCurrentFont(font);
 }
 
 /*!
@@ -840,10 +838,8 @@ void QFontDialog::setCurrentFont(const QFont &font)
 QFont QFontDialog::currentFont() const
 {
     Q_D(const QFontDialog);
-    if (d->canBeNativeDialog()) {
-        if (const QPlatformFontDialogHelper *helper = d->platformFontDialogHelper())
-            return helper->currentFont();
-    }
+    if (const QPlatformFontDialogHelper *helper = d->platformFontDialogHelper())
+        return helper->currentFont();
     return d->sampleEdit->font();
 }