LibGUI: Port AbstractThemePreview::set_theme_from_file to Core::Stream

Author: https://github.com/krkk
Commit: ca7648b1ae
Pull-request: https://github.com/SerenityOS/serenity/pull/16963
Reviewed-by: https://github.com/MacDue

Userland/Libraries/LibGUI/AbstractThemePreview.h

@@ -24,7 +24,7 @@ public:
 
     Gfx::Palette const& preview_palette() const { return m_preview_palette; }
     void set_preview_palette(Gfx::Palette const&);
-    ErrorOr<void> set_theme_from_file(Core::File&);
+    ErrorOr<void> set_theme_from_file(StringView path, NonnullOwnPtr<Core::Stream::File>);
     void set_theme(Core::AnonymousBuffer const&);
 
     void paint_window(StringView title, Gfx::IntRect const& rect, Gfx::WindowTheme::WindowState, Gfx::Bitmap const& icon, int button_count = 3);