Remove the sign-in menu item on macOS.

chrome/browser/signin/signin_ui_util.h

Index: chrome/browser/signin/signin_ui_util.h
diff --git a/chrome/browser/signin/signin_ui_util.h b/chrome/browser/signin/signin_ui_util.h
index d5b1406fa7848c603da2d467b653b7733685607d..d56683894628373685e092112ae8e1c3125fd572 100644
--- a/chrome/browser/signin/signin_ui_util.h
+++ b/chrome/browser/signin/signin_ui_util.h
@@ -20,10 +20,6 @@ namespace signin_ui_util {
 // The maximum number of times to show the welcome tutorial for an upgrade user.
 const int kUpgradeWelcomeTutorialShowMax = 1;
 
-// Returns the label that should be displayed in the signin menu (i.e.
-// "Sign in to Chromium", "Signin Error...", etc).
-base::string16 GetSigninMenuLabel(Profile* profile);
-
 void GetStatusLabelsForAuthError(Profile* profile,
                                  const SigninManagerBase& signin_manager,
                                  base::string16* status_label,