- 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_mac.h
void UpdateDraggableRegions(
      const std::vector<DraggableRegion>& regions) override;
  void ShowWindowButton(NSWindowButton button);
  void InstallView();
  void UninstallView();
  
  
  void UpdateDraggableRegionViews(const std::vector<DraggableRegion>& regions);
  void RegisterInputEventObserver(content::RenderViewHost* host);
  void UnregisterInputEventObserver(content::RenderViewHost* host);
  base::scoped_nsobject<AtomNSWindow> window_;
  base::scoped_nsobject<AtomNSWindowDelegate> window_delegate_;
  
  id wheel_event_monitor_;
  
  base::scoped_nsobject<FullSizeContentView> content_view_;
  std::vector<DraggableRegion> draggable_regions_;
  bool is_kiosk_;
  NSInteger attention_request_id_;  
  
  NSApplicationPresentationOptions kiosk_options_;
  
  TitleBarStyle title_bar_style_;
  
  bool is_edge_;
  DISALLOW_COPY_AND_ASSIGN(NativeWindowMac);
};
}  
#endif