Implement menu bar toggling

src/atom.coffee

@@ -503,7 +503,11 @@ class Atom extends Model
     @packages.activate()
     @keymaps.loadUserKeymap()
     @requireUserInitScript() unless safeMode
+
     @menu.update()
+    @subscribe @config.onDidChange 'core.autoHideMenuBar', ({newValue}) =>
+      @setAutoHideMenuBar(newValue)
+    @setAutoHideMenuBar(true) if @config.get('core.autoHideMenuBar')
 
     maximize = dimensions?.maximized and process.platform isnt 'darwin'
     @displayWindow({maximize})
@@ -723,3 +727,6 @@ class Atom extends Model
 
   setBodyPlatformClass: ->
     document.body.classList.add("platform-#{process.platform}")
+
+  setAutoHideMenuBar: (autoHide) ->
+    ipc.send('call-window-method', 'setAutoHideMenuBar', autoHide)

src/window-event-handler.coffee

@@ -60,6 +60,8 @@ class WindowEventHandler
       atom.reload()
 
     @subscribeToCommand $(window), 'window:toggle-dev-tools', -> atom.toggleDevTools()
+    @subscribeToCommand $(window), 'window:toggle-menu-bar', ->
+      atom.config.set('core.autoHideMenuBar', !atom.config.get('core.autoHideMenuBar'))
 
     @subscribeToCommand $(document), 'core:focus-next', @focusNext