* Electron version: 1.8.2
* Operating system: macos 10.13.3

Reproducing repo: https://github.com/ibash/electron-webkit-app-drag

Demonstrates a bug where `-webkit-app-region: drag` causes a browser view in front of it to miss click events. Oddly - it does not prevent hover events.

Steps:
1. Clone https://github.com/ibash/electron-webkit-app-drag, `yarn install`, `yarn start`
2. Click "button1"
3. Click "button2"

Expected:

Clicking button1 or button2 pops up an alert: "button clicked!"

Actual:

Only clicking button2 pops up an alert: "button clicked!"

atom/browser/api/atom_api_browser_window.cc
#include "atom/common/native_mate_converters/file_path_converter.h"
#include "atom/common/native_mate_converters/gfx_converter.h"
#include "atom/common/native_mate_converters/gurl_converter.h"
#include "atom/common/native_mate_converters/image_converter.h"
#include "atom/common/native_mate_converters/string16_converter.h"
#include "atom/common/native_mate_converters/value_converter.h"
#include "atom/common/options_switches.h"
#include "base/command_line.h"
#include "base/threading/thread_task_runner_handle.h"
#include "content/browser/renderer_host/render_widget_host_impl.h"
#include "content/public/browser/render_process_host.h"
#include "content/public/browser/render_view_host.h"
#include "content/public/common/content_switches.h"
#include "native_mate/constructor.h"
#include "native_mate/dictionary.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gl/gpu_switching_manager.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"
#include "ui/base/win/shell.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,