### Issue Details
in frameless windows 
While setting browserview style to draggable by webkit-app-region : drag. the area won't be draggable after that
and it can not move main window 
### Electron Version:
11.0.1
### Operating System:
Windows 10 (1803)
Last Known Working Electron version:
not found
### Expected Behavior
Browser view moves the main window while I set the style of the body or one of the area to
-webkit-app-region: drag;

### Actual Behavior
nothing happen in browserview after styling -webkit-app-region: drag;

I know it is mention that in 11 version it is fixed. but it still dosn't work 

### To Reproduce
https://gist.github.com/pejmanpesyan/8540aad65e7c6980c45f23e5eaafafb9

shell/browser/native_window_views.cc
if (IsVisible())
    widget()->Maximize();
  else
    widget()->native_widget_private()->Show(ui::SHOW_STATE_MAXIMIZED,
                                            gfx::Rect());
}
#endif
void NativeWindowViews::Unmaximize() {
#if defined(OS_WIN)
  if (!(::GetWindowLong(GetAcceleratedWidget(), GWL_STYLE) & WS_THICKFRAME)) {
    SetBounds(restore_bounds_, false);
    return;
  }
#endif
  widget()->Restore();
}
bool NativeWindowViews::IsMaximized() {