- Electron version: v1.3.3
- Operating system: OS X 10.11.6

v1.3.3 broke the detection of the `scroll-touch-begin` and `scroll-touch-end` events for me within a `webview`. It looks like the pull request #6754 caused this issue. v1.3.2 works as expected.

Behavior that I'm observing on v1.3.3:
- Most of the time, the `scroll-touch-*` events are not emitted when the cursor is on top of a `webview`.
- The `scroll-touch-*` events seem to be emitted _only once_ when the cursor is on a `webview` and on a scrollable element. The scrollable elements in my app have no native scrollbar set (they have the style `overflow: hidden;` set instead of `overflow: scroll;`). This is the case in which I need to receive the `scroll-touch-*` events.
- The `scroll-touch-*` events seem to work fine when the cursor is outside of the `webview` tag.

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::MessageLoop::current()->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(