* 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
auto* existing_preferences =
        WebContentsPreferences::FromWebContents(web_contents->web_contents());
    base::DictionaryValue web_preferences_dict;
    if (mate::ConvertFromV8(isolate, web_preferences.GetHandle(),
                        &web_preferences_dict)) {
      existing_preferences->web_preferences()->Clear();
      existing_preferences->Merge(web_preferences_dict);
    }
  } else {
    
    web_contents = WebContents::Create(isolate, web_preferences);
  }
  Init(isolate, wrapper, options, web_contents);
}
void BrowserWindow::Init(v8::Isolate* isolate,
                         v8::Local<v8::Object> wrapper,
                         const mate::Dictionary& options,
                         mate::Handle<class WebContents> web_contents) {
  web_contents_.Reset(isolate, web_contents.ToV8());
  api_web_contents_ = web_contents.get();
  api_web_contents_->AddObserver(this);
  Observe(api_web_contents_->web_contents());
  
  mate::Dictionary(isolate, web_contents->GetWrapper()).Set(
      "browserWindowOptions", options);
  
  mate::Handle<BrowserWindow> parent;
  if (options.Get("parent", &parent) && !parent.IsEmpty())