- 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.cc
}
void NativeWindow::SetMenu(AtomMenuModel* menu) {
}
void NativeWindow::SetParentWindow(NativeWindow* parent) {
  parent_ = parent;
}
void NativeWindow::FocusOnWebView() {
  web_contents()->GetRenderViewHost()->GetWidget()->Focus();
}
void NativeWindow::BlurWebView() {
  web_contents()->GetRenderViewHost()->GetWidget()->Blur();
}
bool NativeWindow::IsWebViewFocused() {
  auto host_view = web_contents()->GetRenderViewHost()->GetWidget()->GetView();
  return host_view && host_view->HasFocus();
}
void NativeWindow::SetAutoHideMenuBar(bool auto_hide) {
}
bool NativeWindow::IsMenuBarAutoHide() {
  return false;
}
void NativeWindow::SetMenuBarVisibility(bool visible) {
}
bool NativeWindow::IsMenuBarVisible() {
  return true;
}
double NativeWindow::GetAspectRatio() {
  return aspect_ratio_;
}
gfx::Size NativeWindow::GetAspectRatioExtraSize() {