- 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
#include "native_mate/dictionary.h"
#include "ui/gfx/geometry/rect.h"
#if defined(TOOLKIT_VIEWS)
#include "atom/browser/native_window_views.h"
#endif
#if defined(OS_WIN)
#include "atom/browser/ui/win/taskbar_host.h"
#endif
#include "atom/common/node_includes.h"
#if defined(OS_WIN)
namespace mate {
template<>
struct Converter<atom::TaskbarHost::ThumbarButton> {
  static bool FromV8(v8::Isolate* isolate, v8::Handle<v8::Value> val,
                     atom::TaskbarHost::ThumbarButton* out) {
    mate::Dictionary dict;
    if (!ConvertFromV8(isolate, val, &dict))
      return false;
    dict.Get("click", &(out->clicked_callback));
    dict.Get("tooltip", &(out->tooltip));
    dict.Get("flags", &out->flags);
    return dict.Get("icon", &(out->icon));
  }
};
}  
#endif
namespace atom {
namespace api {
namespace {
v8::Local<v8::Value> ToBuffer(v8::Isolate* isolate, void* val, int size) {