- 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_->DestroyWebContents();
  RemoveFromWeakMap();
  window_->RemoveObserver(this);
  
  
  MarkDestroyed();
  Emit("closed");
  RemoveFromParentChildWindows();
  
  base::MessageLoop::current()->PostTask(FROM_HERE, GetDestroyClosure());
}
void Window::OnWindowBlur() {
  Emit("blur");
}
void Window::OnWindowFocus() {
  Emit("focus");
}
void Window::OnWindowShow() {
  Emit("show");
}
void Window::OnWindowHide() {
  Emit("hide");
}
void Window::OnReadyToShow() {
  Emit("ready-to-show");
}
void Window::OnWindowMaximize() {