- 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
base::CommandLine* command_line,
    int process_id) {
  std::string process_type = command_line->GetSwitchValueASCII("type");
  if (process_type != "renderer")
    return;
  
  static const char* const kCommonSwitchNames[] = {
    switches::kStandardSchemes,
  };
  command_line->CopySwitchesFrom(
      *base::CommandLine::ForCurrentProcess(),
      kCommonSwitchNames, arraysize(kCommonSwitchNames));
  
  if (!g_custom_service_worker_schemes.empty())
    command_line->AppendSwitchASCII(switches::kRegisterServiceWorkerSchemes,
                                    g_custom_service_worker_schemes);
#if defined(OS_WIN)
  
  PWSTR current_app_id;
  if (SUCCEEDED(GetCurrentProcessExplicitAppUserModelID(&current_app_id))) {
    command_line->AppendSwitchNative(switches::kAppUserModelId, current_app_id);
    CoTaskMemFree(current_app_id);
  }
#endif
  content::WebContents* web_contents = GetWebContentsFromProcessID(process_id);
  if (!web_contents)
    return;
  WebContentsPreferences::AppendExtraCommandLineSwitches(