- 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
if (web_contents_.IsEmpty())
    return v8::Null(isolate);
  else
    return v8::Local<v8::Value>::New(isolate, web_contents_);
}
void Window::RemoveFromParentChildWindows() {
  if (parent_window_.IsEmpty())
    return;
  mate::Handle<Window> parent;
  if (!mate::ConvertFromV8(isolate(), GetParentWindow(), &parent))
    return;
  parent->child_windows_.Remove(ID());
}
void Window::BuildPrototype(v8::Isolate* isolate,
                            v8::Local<v8::FunctionTemplate> prototype) {
  prototype->SetClassName(mate::StringToV8(isolate, "BrowserWindow"));
  mate::ObjectTemplateBuilder(isolate, prototype->PrototypeTemplate())
      .MakeDestroyable()
      .SetMethod("close", &Window::Close)
      .SetMethod("focus", &Window::Focus)
      .SetMethod("blur", &Window::Blur)
      .SetMethod("isFocused", &Window::IsFocused)
      .SetMethod("show", &Window::Show)
      .SetMethod("showInactive", &Window::ShowInactive)
      .SetMethod("hide", &Window::Hide)
      .SetMethod("isVisible", &Window::IsVisible)
      .SetMethod("isEnabled", &Window::IsEnabled)
      .SetMethod("maximize", &Window::Maximize)
      .SetMethod("unmaximize", &Window::Unmaximize)