- 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/api/atom_api_window.cc
api_web_contents_ = web_contents.get();
  
  mate::Dictionary(isolate, web_contents->GetWrapper()).Set(
      "browserWindowOptions", options);
  
  mate::Handle<Window> parent;
  if (options.Get("parent", &parent))
    parent_window_.Reset(isolate, parent.ToV8());
  
  window_.reset(NativeWindow::Create(
      web_contents->managed_web_contents(),
      options,
      parent.IsEmpty() ? nullptr : parent->window_.get()));
  web_contents->SetOwnerWindow(window_.get());
#if defined(TOOLKIT_VIEWS)
  
  mate::Handle<NativeImage> icon;
  if (options.Get(options::kIcon, &icon))
    SetIcon(icon);
#endif
  window_->InitFromOptions(options);
  window_->AddObserver(this);
  InitWith(isolate, wrapper);
  AttachAsUserData(window_.get());
  
  
  if (!parent.IsEmpty())
    parent->child_windows_.Set(isolate, ID(), wrapper);
}
Window::~Window() {