As in topic. API currently offers fixed ratio only for Mac but not for Windows
shell/browser/native_window_views.cc
SetFullScreen(kiosk);
}
bool NativeWindowViews::IsKiosk() {
  return IsFullscreen();
}
bool NativeWindowViews::IsTabletMode() const {
#if defined(OS_WIN)
  return base::win::IsWindows10TabletMode(GetAcceleratedWidget());
#else
  return false;
#endif
}
SkColor NativeWindowViews::GetBackgroundColor() {
  return root_view_->background()->get_color();
}
void NativeWindowViews::SetBackgroundColor(SkColor background_color) {
  
  root_view_->SetBackground(views::CreateSolidBackground(background_color));
#if defined(OS_WIN)
  
  HBRUSH brush = CreateSolidBrush(skia::SkColorToCOLORREF(background_color));
  ULONG_PTR previous_brush =
      SetClassLongPtr(GetAcceleratedWidget(), GCLP_HBRBACKGROUND,
                      reinterpret_cast<LONG_PTR>(brush));
  if (previous_brush)
    DeleteObject((HBRUSH)previous_brush);
  InvalidateRect(GetAcceleratedWidget(), NULL, 1);
#endif
}
void NativeWindowViews::SetHasShadow(bool has_shadow) {