- Electron version:
  1.3.3
- Operating system:
  OSX El Capitan

``` javascript
      function cbError(e) {
         console.error('failure', e);
      }

      navigator.webkitPersistentStorage.requestQuota( 10 * 1024* 1024, function(granted) {
        webkitRequestFileSystem(PERSISTENT, granted, cb, cbError);
      },
      cbError)
```

webkitRequestFileSystem is failing with:

```
FileError {code: 2, name: "SecurityError", message: "It was determined that certain files are unsafe fo… too many calls are being made on file resources."}code: 2message: "It was determined that certain files are unsafe for access within a Web application, or that too many calls are being made on file resources."name: "SecurityError"__proto__: FileError
```

This page is being served from a custom:// scheme if that matters.

atom/browser/atom_browser_client.cc
web_contents, command_line);
}
void AtomBrowserClient::DidCreatePpapiPlugin(
    content::BrowserPpapiHost* host) {
  host->GetPpapiHost()->AddHostFactoryFilter(
      base::WrapUnique(new chrome::ChromeBrowserPepperHostFactory(host)));
}
content::QuotaPermissionContext*
    AtomBrowserClient::CreateQuotaPermissionContext() {
  return new AtomQuotaPermissionContext;
}
void AtomBrowserClient::AllowCertificateError(
    content::WebContents* web_contents,
    int cert_error,
    const net::SSLInfo& ssl_info,
    const GURL& request_url,
    content::ResourceType resource_type,
    bool overridable,
    bool strict_enforcement,
    bool expired_previous_decision,
    const base::Callback<void(bool)>& callback,
    content::CertificateRequestResultType* request) {
  if (delegate_) {
    delegate_->AllowCertificateError(
        web_contents, cert_error, ssl_info, request_url,
        resource_type, overridable, strict_enforcement,
        expired_previous_decision, callback, request);
  }
}
void AtomBrowserClient::SelectClientCertificate(