- 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.h
PROGRESS_NONE,               
    PROGRESS_INDETERMINATE,      
    PROGRESS_ERROR,              
    PROGRESS_PAUSED,             
    PROGRESS_NORMAL,             
  };
  virtual void SetProgressBar(double progress,
                              const ProgressState state) = 0;
  virtual void SetOverlayIcon(const gfx::Image& overlay,
                              const std::string& description) = 0;
  
  virtual void SetVisibleOnAllWorkspaces(bool visible) = 0;
  virtual bool IsVisibleOnAllWorkspaces() = 0;
  
  virtual void FocusOnWebView();
  virtual void BlurWebView();
  virtual bool IsWebViewFocused();
  
  virtual void SetAutoHideMenuBar(bool auto_hide);
  virtual bool IsMenuBarAutoHide();
  virtual void SetMenuBarVisibility(bool visible);
  virtual bool IsMenuBarVisible();
  
  double GetAspectRatio();
  gfx::Size GetAspectRatioExtraSize();
  virtual void SetAspectRatio(double aspect_ratio, const gfx::Size& extra_size);
  base::WeakPtr<NativeWindow> GetWeakPtr() {