* Electron version: 1.6.0
* Operating system: MacOS 10.12.2

### Expected behavior

'scroll-touch-end' emits when trackpad scrolling ends.

### Actual behavior

The begin event emits, but not the end

### How to reproduce

Example repo: https://github.com/pfrazee/electron-bug-no-scroll-touch-end

atom/browser/native_window.cc
WindowList::WindowCloseCancelled(this);
  
  window_unresposive_closure_.Cancel();
}
void NativeWindow::DidFirstVisuallyNonEmptyPaint() {
  if (IsVisible())
    return;
  
  
  const auto view = web_contents()->GetRenderWidgetHostView();
  view->Show();
  view->SetSize(GetContentSize());
  
  base::ThreadTaskRunnerHandle::Get()->PostTask(
      FROM_HERE,
      base::Bind(&NativeWindow::NotifyReadyToShow, GetWeakPtr()));
}
bool NativeWindow::OnMessageReceived(const IPC::Message& message) {
  bool handled = true;
  IPC_BEGIN_MESSAGE_MAP(NativeWindow, message)
    IPC_MESSAGE_HANDLER(AtomViewHostMsg_UpdateDraggableRegions,
                        UpdateDraggableRegions)
    IPC_MESSAGE_UNHANDLED(handled = false)
  IPC_END_MESSAGE_MAP()
  return handled;
}
void NativeWindow::UpdateDraggableRegions(