- 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
gfx::Size extra_size;
  args->GetNext(&extra_size);
  window_->SetAspectRatio(aspect_ratio, extra_size);
}
void Window::SetParentWindow(v8::Local<v8::Value> value,
                             mate::Arguments* args) {
  if (IsModal()) {
    args->ThrowError("Can not be called for modal window");
    return;
  }
  mate::Handle<Window> parent;
  if (value->IsNull()) {
    RemoveFromParentChildWindows();
    parent_window_.Reset();
    window_->SetParentWindow(nullptr);
  } else if (mate::ConvertFromV8(isolate(), value, &parent)) {
    parent_window_.Reset(isolate(), value);
    window_->SetParentWindow(parent->window_.get());
    parent->child_windows_.Set(isolate(), ID(), GetWrapper());
  } else {
    args->ThrowError("Must pass BrowserWindow instance or null");
  }
}
v8::Local<v8::Value> Window::GetParentWindow() const {