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
browser_context_->prefs()->SetFilePath(
      prefs::kDownloadDefaultDirectory, path);
}
void Session::EnableNetworkEmulation(const mate::Dictionary& options) {
  std::unique_ptr<brightray::DevToolsNetworkConditions> conditions;
  bool offline = false;
  double latency, download_throughput, upload_throughput;
  if (options.Get("offline", &offline) && offline) {
    conditions.reset(new brightray::DevToolsNetworkConditions(offline));
  } else {
    options.Get("latency", &latency);
    options.Get("downloadThroughput", &download_throughput);
    options.Get("uploadThroughput", &upload_throughput);
    conditions.reset(
        new brightray::DevToolsNetworkConditions(false,
                                                 latency,
                                                 download_throughput,
                                                 upload_throughput));
  }
  browser_context_->network_controller_handle()->SetNetworkState(
      devtools_network_emulation_client_id_, std::move(conditions));
  browser_context_->network_delegate()->SetDevToolsNetworkEmulationClientId(
      devtools_network_emulation_client_id_);
}
void Session::DisableNetworkEmulation() {