* 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
ScheduleUnresponsiveEvent(50);
}
void NativeWindow::RendererResponsive(content::WebContents* source) {
  window_unresposive_closure_.Cancel();
  for (NativeWindowObserver& observer : observers_)
    observer.OnRendererResponsive();
}
void NativeWindow::NotifyWindowClosed() {
  if (is_closed_)
    return;
  WindowList::RemoveWindow(this);
  is_closed_ = true;
  for (NativeWindowObserver& observer : observers_)
    observer.OnWindowClosed();
}
void NativeWindow::NotifyWindowBlur() {