- 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
.SetMethod("focusOnWebView", &Window::FocusOnWebView)
      .SetMethod("blurWebView", &Window::BlurWebView)
      .SetMethod("isWebViewFocused", &Window::IsWebViewFocused)
      .SetMethod("setProgressBar", &Window::SetProgressBar)
      .SetMethod("setOverlayIcon", &Window::SetOverlayIcon)
      .SetMethod("setThumbarButtons", &Window::SetThumbarButtons)
      .SetMethod("setMenu", &Window::SetMenu)
      .SetMethod("setAutoHideMenuBar", &Window::SetAutoHideMenuBar)
      .SetMethod("isMenuBarAutoHide", &Window::IsMenuBarAutoHide)
      .SetMethod("setMenuBarVisibility", &Window::SetMenuBarVisibility)
      .SetMethod("isMenuBarVisible", &Window::IsMenuBarVisible)
      .SetMethod("setVisibleOnAllWorkspaces",
                 &Window::SetVisibleOnAllWorkspaces)
      .SetMethod("isVisibleOnAllWorkspaces",
                 &Window::IsVisibleOnAllWorkspaces)
#if defined(OS_WIN)
      .SetMethod("hookWindowMessage", &Window::HookWindowMessage)
      .SetMethod("isWindowMessageHooked", &Window::IsWindowMessageHooked)
      .SetMethod("unhookWindowMessage", &Window::UnhookWindowMessage)
      .SetMethod("unhookAllWindowMessages", &Window::UnhookAllWindowMessages)
      .SetMethod("setThumbnailClip", &Window::SetThumbnailClip)
      .SetMethod("setThumbnailToolTip", &Window::SetThumbnailToolTip)
#endif
#if defined(TOOLKIT_VIEWS)
      .SetMethod("setIcon", &Window::SetIcon)
#endif
      .SetProperty("id", &Window::ID)
      .SetProperty("webContents", &Window::WebContents);
}
v8::Local<v8::Value> Window::From(v8::Isolate* isolate,