* **Electron Version:**
  4.0.2
* **Operating System:**
  macOS 10.14.3
* **Last Known Working Electron version:**:
  1.7

### Expected Behavior
When creating a BrowserWindow it should not appear in the dock menu by defaults.

### Actual Behavior
It appears in the dock menu (example: `raven` in https://electronjs.org/docs/tutorial/macos-dock)

### To Reproduce
Just create new BrowserWindow, then right click on the app icon in the dock. (see https://electronjs.org/docs/tutorial/macos-dock)

At least it should be a way to control that, this can be achieve for top level window with:
`[window_ setExcludedFromWindowsMenu:YES];`, indeed [window isExcludedFromWindowsMenu] returns false by default, see

https://developer.apple.com/documentation/appkit/nsapplication/1428625-removewindowsitem
`Use the isExcludedFromWindowsMenu method of NSWindow if you want the item to remain excluded from the Window menu.`
https://developer.apple.com/documentation/appkit/nswindow/1419175-isexcludedfromwindowsmenu

atom/browser/native_window.h
PROGRESS_NONE,           
    PROGRESS_INDETERMINATE,  
    PROGRESS_ERROR,          
    PROGRESS_PAUSED,         
    PROGRESS_NORMAL,         
  };
  virtual void SetProgressBar(double progress, const ProgressState state) = 0;
  virtual void SetOverlayIcon(const gfx::Image& overlay,
                              const std::string& description) = 0;
  
  virtual void SetVisibleOnAllWorkspaces(bool visible,
                                         bool visibleOnFullScreen = false) = 0;
  virtual bool IsVisibleOnAllWorkspaces() = 0;
  virtual void SetAutoHideCursor(bool auto_hide);
  
  virtual void SetVibrancy(const std::string& type);
  
  virtual void SetTouchBar(
      const std::vector<mate::PersistentDictionary>& items);
  virtual void RefreshTouchBarItem(const std::string& item_id);
  virtual void SetEscapeTouchBarItem(const mate::PersistentDictionary& item);
  
  virtual void SelectPreviousTab();