win: allow dynamic switch dark mode

Zhao Yuhang

2023-12-22 e33059ee1ef7e1be07490ad0245676ded42589f4

 src/widgets/widgetwindowagent.cpp

@@ -36,9 +36,7 @@
        w->setAttribute(Qt::WA_DontCreateNativeAncestors);
        w->setAttribute(Qt::WA_NativeWindow);

        if (!d->setup(w, new WidgetItemDelegate())) {
            return false;
        }
        d->setup(w, new WidgetItemDelegate());
        d->hostWidget = w;

#ifdef Q_OS_WINDOWS
@@ -57,9 +55,6 @@
        if (!d->context->setTitleBar(w)) {
            return;
        }
#ifdef Q_OS_MACOS
        d->setupMacOSTitleBar(w);
#endif
        Q_EMIT titleBarWidgetChanged(w);
    }