- 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.h
class Window : public mate::TrackableObject<Window>,
               public NativeWindowObserver {
 public:
  static mate::WrappableBase* New(mate::Arguments* args);
  static void BuildPrototype(v8::Isolate* isolate,
                             v8::Local<v8::FunctionTemplate> prototype);
  
  static v8::Local<v8::Value> From(v8::Isolate* isolate,
                                   NativeWindow* native_window);
  NativeWindow* window() const { return window_.get(); }
 protected:
  Window(v8::Isolate* isolate, v8::Local<v8::Object> wrapper,
         const mate::Dictionary& options);
  ~Window() override;
  
  void WillCloseWindow(bool* prevent_default) override;
  void WillDestroyNativeObject() override;
  void OnWindowClosed() override;
  void OnWindowBlur() override;
  void OnWindowFocus() override;
  void OnWindowShow() override;
  void OnWindowHide() override;
  void OnReadyToShow() override;
  void OnWindowMaximize() override;
  void OnWindowUnmaximize() override;
  void OnWindowMinimize() override;
  void OnWindowRestore() override;
  void OnWindowResize() override;
  void OnWindowMove() override;