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 9eb883ff857d14c4e79918121db1dc66c50218b0..58989e8a27a944845cb6d08ad184ce10ca06a61f 100644
--- a/chrome/browser/ui/toolbar/wrench_menu_model.cc
+++ b/chrome/browser/ui/toolbar/wrench_menu_model.cc
@@ -535,12 +535,14 @@ void WrenchMenuModel::Build(bool is_new_menu, bool supports_new_separators) {
   AddSeparator(ui::NORMAL_SEPARATOR);
 
 #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()) {
+    // No "Sign in to Chromium..." menu item on ChromeOS.

[Andrew T Wilson (Slow), 2013/02/04 15:41:48]

Move this comment one line up so it's clear it refers to the #ifdef.

[Adrian Kuegel, 2013/02/05 10:55:15]

Done.

+    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);