As in topic. API currently offers fixed ratio only for Mac but not for Windows
shell/browser/native_window_views.cc
display::Screen::GetScreen()->GetDisplayNearestPoint(GetPosition());
      SetBounds(display.bounds(), false);
    } else {
      SetBounds(restore_bounds_, false);
    }
    return;
  }
  
  
  widget()->SetFullscreen(fullscreen);
  
  
  
  
  if (leaving_fullscreen && !IsVisible())
    FlipWindowStyle(GetAcceleratedWidget(), true, WS_VISIBLE);
#else
  if (IsVisible())
    widget()->SetFullscreen(fullscreen);
  else if (fullscreen)
    widget()->native_widget_private()->Show(ui::SHOW_STATE_FULLSCREEN,
                                            gfx::Rect());
  
  if (fullscreen)
    SetMenuBarVisibility(false);
  else
    SetMenuBarVisibility(!IsMenuBarAutoHide());
#endif
}
bool NativeWindowViews::IsFullscreen() const {