As in topic. API currently offers fixed ratio only for Mac but not for Windows
shell/browser/native_window_views.cc
if (options.Get(options::kSkipTaskbar, &skip_taskbar) && skip_taskbar) {
      state_atom_list.push_back(x11::GetAtom("_NET_WM_STATE_SKIP_TASKBAR"));
    }
    
    if (fullscreen) {
      state_atom_list.push_back(x11::GetAtom("_NET_WM_STATE_FULLSCREEN"));
    }
    if (parent) {
      
      window_type = "dialog";
      
      if (is_modal())
        state_atom_list.push_back(x11::GetAtom("_NET_WM_STATE_MODAL"));
    }
    if (!state_atom_list.empty())
      ui::SetAtomArrayProperty(static_cast<x11::Window>(GetAcceleratedWidget()),
                               "_NET_WM_STATE", "ATOM", state_atom_list);
    
    if (!window_type.empty())
      SetWindowType(static_cast<x11::Window>(GetAcceleratedWidget()),
                    window_type);
  }
#endif
#if defined(OS_WIN)
  if (!has_frame()) {
    
    
    DWORD frame_style = WS_CAPTION | WS_OVERLAPPED;
    if (resizable_)
      frame_style |= WS_THICKFRAME;