- 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
std::vector<int> result(2);
  gfx::Size size = window_->GetSize();
  result[0] = size.width();
  result[1] = size.height();
  return result;
}
void Window::SetContentSize(int width, int height, mate::Arguments* args) {
  bool animate = false;
  args->GetNext(&animate);
  window_->SetContentSize(gfx::Size(width, height), animate);
}
std::vector<int> Window::GetContentSize() {
  std::vector<int> result(2);
  gfx::Size size = window_->GetContentSize();
  result[0] = size.width();
  result[1] = size.height();
  return result;
}
void Window::SetMinimumSize(int width, int height) {
  window_->SetMinimumSize(gfx::Size(width, height));
}
std::vector<int> Window::GetMinimumSize() {
  std::vector<int> result(2);
  gfx::Size size = window_->GetMinimumSize();
  result[0] = size.width();
  result[1] = size.height();
  return result;
}
void Window::SetMaximumSize(int width, int height) {