### 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_LINUX)
  aura::Window* window = GetNativeWindow();
  if (window)
    window->RemovePreTargetHandler(this);
#endif
}
void NativeWindowViews::DeleteDelegate() {
  if (is_modal() && this->parent()) {
    auto* parent = this->parent();
    
    static_cast<NativeWindowViews*>(parent)->DecrementChildModals();
    
    parent->Focus(true);
  }
  NotifyWindowClosed();
}
views::View* NativeWindowViews::GetInitiallyFocusedView() {
  return focused_view_;
}
bool NativeWindowViews::CanResize() const {
  return resizable_;
}
bool NativeWindowViews::CanMaximize() const {
  return resizable_ && maximizable_;
}
bool NativeWindowViews::CanMinimize() const {