* Electron Version: 3.0.0-beta.1 ~ 3.0.0-beta.6
* Operating System (Platform and Version): Ubuntu 16.04.2 LTS
* Last known working Electron version: versions before 3.0.0-beta.1

**Expected Behavior**
Console prints out `time to print stuff` when `Ctrl+P` is pressed.
```
const {Menu, MenuItem} = require('electron')
const menu = new Menu()
  
app.on('ready', () => {
  createWindow()
  menu.append(new MenuItem({
    label: 'Print',
    accelerator: 'CmdOrCtrl+P',
    click: () => { console.log('time to print stuff') }
  }))
  Menu.setApplicationMenu(menu)
})
```
https://github.com/hackjutsu/electron-quick-start/commit/6ceb5d7dcd2d946c071b43a3fdd1b0434ddebff5
**Actual behavior**
No output. The accelerator event is not triggered.

**To Reproduce**
```sh
git clone https://github.com/hackjutsu/electron-quick-start
cd electron-quick-start
npm install
npm run start
```
Try pressing `Ctrl+P`, and observe the output. (nothing happen...)
Change the electron version back to 2.0.0 in `pakcage.json`
```sh
npm install
npm run start
```
Try pressing `Ctrl+P`, and observe the output. (the log `time to print stuff` will show up in console)

atom/browser/native_window_views.cc
#if defined(USE_X11)
  if (menu_model == nullptr)
    global_menu_bar_.reset();
  if (!global_menu_bar_ && ShouldUseGlobalMenuBar())
    global_menu_bar_.reset(new GlobalMenuBarX11(this));
  
  if (global_menu_bar_ && global_menu_bar_->IsServerStarted()) {
    global_menu_bar_->SetMenu(menu_model);
    return;
  }
#endif
  
  gfx::Size content_size = GetContentSize();
  bool should_reset_size = use_content_size_ && has_frame() &&
                           !IsMenuBarAutoHide() &&
                           ((!!menu_model) != root_view_->HasMenu());
  root_view_->SetMenu(menu_model);
  if (should_reset_size) {
    
    int menu_bar_height = root_view_->GetMenuBarHeight();
    extensions::SizeConstraints constraints = GetContentSizeConstraints();
    if (constraints.HasMinimumSize()) {
      gfx::Size min_size = constraints.GetMinimumSize();
      min_size.set_height(min_size.height() + menu_bar_height);