* **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
#if defined(OS_WIN)
  return minimizable_;
#elif defined(USE_X11)
  return true;
#endif
}
base::string16 NativeWindowViews::GetWindowTitle() const {
  return base::UTF8ToUTF16(title_);
}
views::View* NativeWindowViews::GetContentsView() {
  return root_view_.get();
}
bool NativeWindowViews::ShouldDescendIntoChildForEventHandling(
    gfx::NativeView child,
    const gfx::Point& location) {
  
  if (draggable_region() &&
      draggable_region()->contains(location.x(), location.y()))
    return false;
  
  if (!has_frame() && CanResize()) {
    FramelessView* frame =
        static_cast<FramelessView*>(widget()->non_client_view()->frame_view());
    return frame->ResizingBorderHitTest(location) == HTNOWHERE;
  }
  return true;
}
views::ClientView* NativeWindowViews::CreateClientView(views::Widget* widget) {