Revert of Delete dead signin code (SigninGlobalError)

chrome/browser/ui/cocoa/browser_window_controller.mm

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/ui/cocoa/browser_window_controller.h"
 
 #include <cmath>
 #include <numeric>
 
 #include "base/command_line.h"
@@ skipping 1130 matching lines @@
         }
         case IDC_PRESENTATION_MODE: {
           if (NSMenuItem* menuItem = base::mac::ObjCCast<NSMenuItem>(item)) {
             [menuItem setTitle:[self titleForFullscreenMenuItem]];
 
             if (chrome::mac::SupportsSystemFullscreen())
               [menuItem setAlternate:YES];
           }
           break;
         }
+        case IDC_SHOW_SIGNIN: {
+          Profile* original_profile =
+              browser_->profile()->GetOriginalProfile();
+          [AppController updateSigninItem:item
+                               shouldShow:enable
+                           currentProfile:original_profile];
+          break;
+        }
         case IDC_BOOKMARK_PAGE: {
           // Extensions have the ability to hide the bookmark page menu item.
           // This only affects the bookmark page menu item under the main menu.
           // The bookmark page menu item under the wrench menu has its
           // visibility controlled by WrenchMenuModel.
           bool shouldHide =
               chrome::ShouldRemoveBookmarkThisPageUI(browser_->profile());
           NSMenuItem* menuItem = base::mac::ObjCCast<NSMenuItem>(item);
           [menuItem setHidden:shouldHide];
           break;
@@ skipping 1098 matching lines @@
 
 - (BOOL)supportsBookmarkBar {
   return [self supportsWindowFeature:Browser::FEATURE_BOOKMARKBAR];
 }
 
 - (BOOL)isTabbedWindow {
   return browser_->is_type_tabbed();
 }
 
 @end  // @implementation BrowserWindowController(WindowType)