### 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 defined(OS_WIN)
  return ::IsWindowEnabled(GetAcceleratedWidget());
#elif defined(OS_LINUX)
#if defined(USE_X11)
  if (!features::IsUsingOzonePlatform()) {
    return !event_disabler_.get();
  }
#endif
  NOTIMPLEMENTED();
  return true;
#endif
}
void NativeWindowViews::IncrementChildModals() {
  num_modal_children_++;
  SetEnabledInternal(ShouldBeEnabled());
}
void NativeWindowViews::DecrementChildModals() {
  if (num_modal_children_ > 0) {
    num_modal_children_--;
  }
  SetEnabledInternal(ShouldBeEnabled());
}
void NativeWindowViews::SetEnabled(bool enable) {
  if (enable != is_enabled_) {
    is_enabled_ = enable;
    SetEnabledInternal(ShouldBeEnabled());
  }
}
bool NativeWindowViews::ShouldBeEnabled() {