- 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
#include "base/stl_util.h"
#include "base/strings/string_util.h"
#include "base/strings/string_number_conversions.h"
#include "chrome/browser/printing/printing_message_filter.h"
#include "chrome/browser/renderer_host/pepper/chrome_browser_pepper_host_factory.h"
#include "chrome/browser/renderer_host/pepper/widevine_cdm_message_filter.h"
#include "chrome/browser/speech/tts_message_filter.h"
#include "content/public/browser/browser_ppapi_host.h"
#include "content/public/browser/client_certificate_delegate.h"
#include "content/public/browser/render_process_host.h"
#include "content/public/browser/render_view_host.h"
#include "content/public/browser/resource_dispatcher_host.h"
#include "content/public/browser/site_instance.h"
#include "content/public/browser/web_contents.h"
#include "content/public/common/web_preferences.h"
#include "net/ssl/ssl_cert_request_info.h"
#include "ppapi/host/ppapi_host.h"
#include "ui/base/l10n/l10n_util.h"
#include "v8/include/v8.h"
namespace atom {
namespace {
bool g_suppress_renderer_process_restart = false;
std::string g_custom_service_worker_schemes = "";
void Noop(scoped_refptr<content::SiteInstance>) {
}
}  
void AtomBrowserClient::SuppressRendererProcessRestartForOnce() {
  g_suppress_renderer_process_restart = true;
}
void AtomBrowserClient::SetCustomServiceWorkerSchemes(