Docs:
https://github.com/electron/electron/blob/master/docs/api/session.md#sesclearstoragedataoptions-callback

I was running into a strange error when calling the `clearStorageData` method. It was saying it was unable to process the argument at index 1, which I was not passing. After some research I found that the callback is currently required, but in my case I did not care to provide one. To fix it, I supplied an empty function. Here is my code:

```
Electron.remote.getCurrentWebContents().session.clearStorageData(
    {
        storages: [
            'appcache',
            'cookies',
            'filesystem',
            'indexdb',
            'localstorage',
            'shadercache',
            'websql',
            'serviceworkers',
        ],
        quotas: [
            'temporary',
            'persistent',
            'syncable',
        ],
    },
    function() {} // <--- I shouldn't have to do this
);
```
- Electron version: 1.2.7
- Operating system: macOS

atom/browser/api/atom_api_session.cc
v8::Local<v8::ObjectTemplate> prototype) {
  mate::ObjectTemplateBuilder(isolate, prototype)
      .MakeDestroyable()
      .SetMethod("resolveProxy", &Session::ResolveProxy)
      .SetMethod("getCacheSize", &Session::DoCacheAction<CacheAction::STATS>)
      .SetMethod("clearCache", &Session::DoCacheAction<CacheAction::CLEAR>)
      .SetMethod("clearStorageData", &Session::ClearStorageData)
      .SetMethod("flushStorageData", &Session::FlushStorageData)
      .SetMethod("setProxy", &Session::SetProxy)
      .SetMethod("setDownloadPath", &Session::SetDownloadPath)
      .SetMethod("enableNetworkEmulation", &Session::EnableNetworkEmulation)
      .SetMethod("disableNetworkEmulation", &Session::DisableNetworkEmulation)
      .SetMethod("setCertificateVerifyProc", &Session::SetCertVerifyProc)
      .SetMethod("setPermissionRequestHandler",
                 &Session::SetPermissionRequestHandler)
      .SetMethod("clearHostResolverCache", &Session::ClearHostResolverCache)
      .SetMethod("allowNTLMCredentialsForDomains",
                 &Session::AllowNTLMCredentialsForDomains)
      .SetMethod("setUserAgent", &Session::SetUserAgent)
      .SetMethod("getUserAgent", &Session::GetUserAgent)
      .SetProperty("cookies", &Session::Cookies)
      .SetProperty("protocol", &Session::Protocol)
      .SetProperty("webRequest", &Session::WebRequest);
}
void SetWrapSession(const WrapSessionCallback& callback) {