Add a SigninAllowed policy.

chrome/browser/ui/toolbar/wrench_menu_model.cc

Index: chrome/browser/ui/toolbar/wrench_menu_model.cc
diff --git a/chrome/browser/ui/toolbar/wrench_menu_model.cc b/chrome/browser/ui/toolbar/wrench_menu_model.cc
index c24ce72e75d39ef854a646af80f59b01cdfab39a..e3420ea49d90f3dc312966a77cfbffe3515aef78 100644
--- a/chrome/browser/ui/toolbar/wrench_menu_model.cc
+++ b/chrome/browser/ui/toolbar/wrench_menu_model.cc
@@ -536,11 +536,13 @@ void WrenchMenuModel::Build(bool is_new_menu, bool supports_new_separators) {
 
 #if !defined(OS_CHROMEOS)
   // No "Sign in to Chromium..." menu item on ChromeOS.
-  const string16 short_product_name =
-      l10n_util::GetStringUTF16(IDS_SHORT_PRODUCT_NAME);
-  AddItem(IDC_SHOW_SYNC_SETUP, l10n_util::GetStringFUTF16(
-      IDS_SYNC_MENU_PRE_SYNCED_LABEL, short_product_name));
-  AddSeparator(ui::NORMAL_SEPARATOR);
+  if (browser_->profile()->GetOriginalProfile()->IsSigninAllowed()) {
+    const string16 short_product_name =
+        l10n_util::GetStringUTF16(IDS_SHORT_PRODUCT_NAME);
+    AddItem(IDC_SHOW_SYNC_SETUP, l10n_util::GetStringFUTF16(
+        IDS_SYNC_MENU_PRE_SYNCED_LABEL, short_product_name));
+    AddSeparator(ui::NORMAL_SEPARATOR);
+  }
 #endif
 
   AddItemWithStringId(IDC_OPTIONS, IDS_SETTINGS);