* Electron version: 1.6.0
* Operating system: MacOS 10.12.2

### Expected behavior

'scroll-touch-end' emits when trackpad scrolling ends.

### Actual behavior

The begin event emits, but not the end

### How to reproduce

Example repo: https://github.com/pfrazee/electron-bug-no-scroll-touch-end

atom/browser/native_window.cc
#include "base/message_loop/message_loop.h"
#include "base/strings/utf_string_conversions.h"
#include "base/threading/thread_task_runner_handle.h"
#include "brightray/browser/inspectable_web_contents.h"
#include "brightray/browser/inspectable_web_contents_view.h"
#include "components/prefs/pref_service.h"
#include "content/browser/renderer_host/render_widget_host_impl.h"
#include "content/public/browser/navigation_entry.h"
#include "content/public/browser/plugin_service.h"
#include "content/public/browser/render_process_host.h"
#include "content/public/browser/render_view_host.h"
#include "content/public/browser/render_widget_host.h"
#include "content/public/browser/render_widget_host_view.h"
#include "content/public/common/content_switches.h"
#include "ipc/ipc_message_macros.h"
#include "native_mate/dictionary.h"
#include "third_party/skia/include/core/SkRegion.h"
#include "ui/gfx/codec/png_codec.h"
#include "ui/gfx/geometry/point.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/geometry/size.h"
#include "ui/gfx/geometry/size_conversions.h"
#include "ui/gl/gpu_switching_manager.h"
#if defined(OS_LINUX) || defined(OS_WIN)
#include "content/public/common/renderer_preferences.h"
#include "ui/gfx/font_render_params.h"
#endif
DEFINE_WEB_CONTENTS_USER_DATA_KEY(atom::NativeWindowRelay);
namespace atom {
NativeWindow::NativeWindow(