### 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
NotifyWindowMove();
}
void NativeWindowViews::HandleKeyboardEvent(
    content::WebContents*,
    const content::NativeWebKeyboardEvent& event) {
#if defined(OS_LINUX)
  if (event.windows_key_code == ui::VKEY_BROWSER_BACK)
    NotifyWindowExecuteAppCommand(kBrowserBackward);
  else if (event.windows_key_code == ui::VKEY_BROWSER_FORWARD)
    NotifyWindowExecuteAppCommand(kBrowserForward);
#endif
  keyboard_event_handler_->HandleKeyboardEvent(event,
                                               root_view_->GetFocusManager());
  root_view_->HandleKeyEvent(event);
}
#if defined(OS_LINUX)
void NativeWindowViews::OnMouseEvent(ui::MouseEvent* event) {
  if (event->type() != ui::ET_MOUSE_PRESSED)
    return;
  if (event->changed_button_flags() == ui::EF_BACK_MOUSE_BUTTON)
    NotifyWindowExecuteAppCommand(kBrowserBackward);
  else if (event->changed_button_flags() == ui::EF_FORWARD_MOUSE_BUTTON)
    NotifyWindowExecuteAppCommand(kBrowserForward);
}
#endif
ui::WindowShowState NativeWindowViews::GetRestoredState() {