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* Electron version: 1.7.0
* Operating system: macOS

### Expected behavior
Electron works with `--debug` or `-debug` argument

<!-- What do you think should happen? -->

### Actual behavior
Electron won't run with arguments above.

<!-- What actually happens? -->

### How to reproduce

I've tried the standalone .app and the npm modules:

- for standalone .app it shows an error and returns a non-zero
(with "IOVARendererID property not found" the welcome window appears and I've manually close it)
![image](https://cloud.githubusercontent.com/assets/3816900/25955449/e4d09a72-369b-11e7-894b-415231293022.png)

- for npm module it just won't start and no error returns
![image](https://cloud.githubusercontent.com/assets/3816900/25955695/84b36dee-369c-11e7-9d19-6014f13d9a50.png)


I can confirm the `--debug` works with previous versions including 1.6.9 beta

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atom/browser/atom_browser_main_parts.h
#ifndef ATOM_BROWSER_ATOM_BROWSER_MAIN_PARTS_H_
#define ATOM_BROWSER_ATOM_BROWSER_MAIN_PARTS_H_
#include <list>
#include <string>
#include "base/callback.h"
#include "base/timer/timer.h"
#include "brightray/browser/browser_main_parts.h"
#include "content/public/browser/browser_context.h"
class BrowserProcess;
namespace atom {
class AtomBindings;
class Browser;
class JavascriptEnvironment;