Remove the sign-in menu item on macOS.

chrome/browser/ui/cocoa/browser_window_command_handler.mm

 // Copyright 2015 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_command_handler.h"
 
 #include "base/logging.h"
 #import "base/mac/foundation_util.h"
 #include "chrome/app/chrome_command_ids.h"
 #import "chrome/browser/app_controller_mac.h"
@@ skipping 115 matching lines @@
       // app_controller_mac.mm actually determines whether the item should
       // be enabled.
       if (NSMenuItem* menuItem = base::mac::ObjCCast<NSMenuItem>(item))
         enable &= !![[menuItem keyEquivalent] length];
       break;
     case IDC_FULLSCREEN: {
       if (NSMenuItem* menuItem = base::mac::ObjCCast<NSMenuItem>(item))
         [menuItem setTitle:GetTitleForFullscreenMenuItem(browser)];
       break;
     }
-    case IDC_SHOW_SIGNIN: {
-      Profile* original_profile = browser->profile()->GetOriginalProfile();
-      [AppController updateSigninItem:item
-                           shouldShow:enable
-                       currentProfile:original_profile];
-      content::RecordAction(
-          base::UserMetricsAction("Signin_Impression_FromMenu"));
-      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 app menu has its visibility
       // controlled by AppMenuModel.
       bool shouldHide =
           chrome::ShouldRemoveBookmarkThisPageUI(browser->profile());
       NSMenuItem* menuItem = base::mac::ObjCCast<NSMenuItem>(item);
       [menuItem setHidden:shouldHide];
       break;
@@ skipping 57 matching lines @@
     // the background" in this case.
     modifierFlags &= ~NSCommandKeyMask;
   }
   chrome::ExecuteCommandWithDisposition(
       FindBrowserForSender(sender, window), command,
       ui::WindowOpenDispositionFromNSEventWithFlags([NSApp currentEvent],
                                                     modifierFlags));
 }
 
 @end