* Electron version: 1.7.7
* Operating system: macOS

### Expected behavior

Entries of `TouchBarScrubber` show entirely

### Actual behavior

Each `ScrubberItem` shows with a "..."

### How to reproduce

Just create a new `TouchBarScrubber` and fill in some `ScrubberItem` and all entries will get a "...":

![image](https://user-images.githubusercontent.com/900690/30519458-1f12dbae-9b97-11e7-8bd7-476796502463.png)

atom/browser/ui/cocoa/atom_touch_bar.h
#ifndef ATOM_BROWSER_UI_COCOA_ATOM_TOUCH_BAR_H_
#define ATOM_BROWSER_UI_COCOA_ATOM_TOUCH_BAR_H_
#import <Cocoa/Cocoa.h>
#include <map>
#include <string>
#include <vector>
#include "atom/browser/native_window.h"
#include "atom/browser/ui/cocoa/touch_bar_forward_declarations.h"
#include "base/mac/scoped_nsobject.h"
#include "native_mate/constructor.h"
#include "native_mate/persistent_dictionary.h"
@interface AtomTouchBar : NSObject<NSScrubberDelegate, NSScrubberDataSource> {
 @protected
  std::vector<mate::PersistentDictionary> ordered_settings_;
  std::map<std::string, mate::PersistentDictionary> settings_;
  id<NSTouchBarDelegate> delegate_;
  atom::NativeWindow* window_;