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
uint32_t quota_mask = 0;
  for (const auto& it : quota_types) {
    auto type = base::ToLowerASCII(it);
    if (type == "temporary")
      quota_mask |= StoragePartition::QUOTA_MANAGED_STORAGE_MASK_TEMPORARY;
    else if (type == "persistent")
      quota_mask |= StoragePartition::QUOTA_MANAGED_STORAGE_MASK_PERSISTENT;
    else if (type == "syncable")
      quota_mask |= StoragePartition::QUOTA_MANAGED_STORAGE_MASK_SYNCABLE;
  }
  return quota_mask;
}
void SetUserAgentInIO(scoped_refptr<net::URLRequestContextGetter> getter,
                      const std::string& accept_lang,
                      const std::string& user_agent) {
  getter->GetURLRequestContext()->set_http_user_agent_settings(
      new net::StaticHttpUserAgentSettings(
          net::HttpUtil::GenerateAcceptLanguageHeader(accept_lang),
          user_agent));
}
}  
namespace mate {
template<>
struct Converter<ClearStorageDataOptions> {
  static bool FromV8(v8::Isolate* isolate,