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
std::unique_ptr<brightray::DevToolsNetworkConditions> conditions;
  browser_context_->network_controller_handle()->SetNetworkState(
      devtools_network_emulation_client_id_, std::move(conditions));
  browser_context_->network_delegate()->SetDevToolsNetworkEmulationClientId(
      std::string());
}
void Session::SetCertVerifyProc(v8::Local<v8::Value> val,
                                mate::Arguments* args) {
  AtomCertVerifier::VerifyProc proc;
  if (!(val->IsNull() || mate::ConvertFromV8(args->isolate(), val, &proc))) {
    args->ThrowError("Must pass null or function");
    return;
  }
  BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
      base::Bind(&SetCertVerifyProcInIO,
                 make_scoped_refptr(browser_context_->GetRequestContext()),
                 proc));
}
void Session::SetPermissionRequestHandler(v8::Local<v8::Value> val,
                                          mate::Arguments* args) {
  AtomPermissionManager::RequestHandler handler;
  if (!(val->IsNull() || mate::ConvertFromV8(args->isolate(), val, &handler))) {
    args->ThrowError("Must pass null or function");
    return;
  }
  auto permission_manager = static_cast<AtomPermissionManager*>(
      browser_context()->GetPermissionManager());
  permission_manager->SetPermissionRequestHandler(handler);
}
void Session::ClearHostResolverCache(mate::Arguments* args) {