As in topic. API currently offers fixed ratio only for Mac but not for Windows
shell/browser/native_window_views.cc
use_content_size_)
    size = ContentBoundsToWindowBounds(gfx::Rect(size)).size();
  widget()->CenterWindow(size);
#if defined(OS_WIN)
  
  if (fullscreen)
    last_window_state_ = ui::SHOW_STATE_FULLSCREEN;
  else
    last_window_state_ = ui::SHOW_STATE_NORMAL;
#endif
#if defined(OS_LINUX)
  
  aura::Window* window = GetNativeWindow();
  if (window)
    window->AddPreTargetHandler(this);
#endif
}
NativeWindowViews::~NativeWindowViews() {
  widget()->RemoveObserver(this);
#if defined(OS_WIN)
  
  SetForwardMouseMessages(false);
#endif
#if defined(OS_LINUX)
  aura::Window* window = GetNativeWindow();
  if (window)
    window->RemovePreTargetHandler(this);
#endif
}
void NativeWindowViews::SetGTKDarkThemeEnabled(bool use_dark_theme) {