- 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/native_window_observer.h
#ifndef ATOM_BROWSER_NATIVE_WINDOW_OBSERVER_H_
#define ATOM_BROWSER_NATIVE_WINDOW_OBSERVER_H_
#include <string>
#include "base/strings/string16.h"
#include "ui/base/window_open_disposition.h"
#include "url/gurl.h"
#if defined(OS_WIN)
#include <windows.h>
#endif
namespace atom {
class NativeWindowObserver {