* **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_views.h
bool CanMinimize() const override;
  base::string16 GetWindowTitle() const override;
  views::View* GetContentsView() override;
  bool ShouldDescendIntoChildForEventHandling(
      gfx::NativeView child,
      const gfx::Point& location) override;
  views::ClientView* CreateClientView(views::Widget* widget) override;
  views::NonClientFrameView* CreateNonClientFrameView(
      views::Widget* widget) override;
  void OnWidgetMove() override;
#if defined(OS_WIN)
  bool ExecuteWindowsCommand(int command_id) override;
#endif
#if defined(OS_WIN)
  
  bool PreHandleMSG(UINT message,
                    WPARAM w_param,
                    LPARAM l_param,
                    LRESULT* result) override;
  void HandleSizeEvent(WPARAM w_param, LPARAM l_param);
  void SetForwardMouseMessages(bool forward);
  static LRESULT CALLBACK SubclassProc(HWND hwnd,
                                       UINT msg,
                                       WPARAM w_param,
                                       LPARAM l_param,
                                       UINT_PTR subclass_id,
                                       DWORD_PTR ref_data);
  static LRESULT CALLBACK MouseHookProc(int n_code,
                                        WPARAM w_param,
                                        LPARAM l_param);