* **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.cc
window_icon_ = base::win::ScopedHICON(CopyIcon(window_icon));
  app_icon_ = base::win::ScopedHICON(CopyIcon(app_icon));
  HWND hwnd = GetAcceleratedWidget();
  SendMessage(hwnd, WM_SETICON, ICON_SMALL,
              reinterpret_cast<LPARAM>(window_icon_.get()));
  SendMessage(hwnd, WM_SETICON, ICON_BIG,
              reinterpret_cast<LPARAM>(app_icon_.get()));
}
#elif defined(USE_X11)
void NativeWindowViews::SetIcon(const gfx::ImageSkia& icon) {
  auto* tree_host = static_cast<views::DesktopWindowTreeHost*>(
      views::DesktopWindowTreeHostX11::GetHostForXID(GetAcceleratedWidget()));
  tree_host->SetWindowIcons(icon, icon);
}
#endif
void NativeWindowViews::OnWidgetActivationChanged(views::Widget* changed_widget,
                                                  bool active) {
  if (changed_widget != widget())
    return;
  if (active)
    NativeWindow::NotifyWindowFocus();
  else
    NativeWindow::NotifyWindowBlur();
  
  if (!active && IsMenuBarAutoHide() && IsMenuBarVisible())
    SetMenuBarVisibility(false);
  root_view_->ResetAltState();
}
void NativeWindowViews::OnWidgetBoundsChanged(views::Widget* changed_widget,