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
const net::ProxyConfig& config,
                  const base::Closure& callback) {
  auto proxy_service = getter->GetURLRequestContext()->proxy_service();
  proxy_service->ResetConfigService(make_scoped_ptr(
      new net::ProxyConfigServiceFixed(config)));
  
  proxy_service->ForceReloadProxyConfig();
  RunCallbackInUI(callback);
}
void SetCertVerifyProcInIO(
    const scoped_refptr<net::URLRequestContextGetter>& context_getter,
    const AtomCertVerifier::VerifyProc& proc) {
  auto request_context = context_getter->GetURLRequestContext();
  static_cast<AtomCertVerifier*>(request_context->cert_verifier())->
      SetVerifyProc(proc);
}
void ClearHostResolverCacheInIO(
    const scoped_refptr<net::URLRequestContextGetter>& context_getter,
    const base::Closure& callback) {
  auto request_context = context_getter->GetURLRequestContext();
  auto cache = request_context->host_resolver()->GetHostCache();
  if (cache) {
    cache->clear();
    DCHECK_EQ(0u, cache->size());
    if (!callback.is_null())
      RunCallbackInUI(callback);
  }
}
void AllowNTLMCredentialsForDomainsInIO(