Adds an error message for authentication errors during managed user creation

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index faa3af31c0335615d710a8bee0a58913ba795740..20857d9194d9a3873a410cb0100131fc5b478ef3 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -14206,6 +14206,9 @@ Some features may be unavailable.  Please check that the profile exists and you
     <message name="IDS_PROFILES_CREATE_REMOTE_ERROR" desc="Message shown when a remote error (for example, a network error) occurs during creation of a new supervised user.">
       Oops! The new supervised user couldn't be created. Please check your network connection and try again later.
     </message>
+    <message name="IDS_PROFILES_CREATE_SIGN_IN_ERROR" desc="Message shown when a sign-in error occurs during creation of a new supervised user.">
+      Oops! The new supervised user couldn't be created. Please make sure you're signed in properly and try again.
+    </message>
     <message name="IDS_PROFILES_CREATE_MANAGED_SIGNED_IN_LABEL" desc="Label for the 'Supervised user' checkbox in the create-profile dialog when the current user is signed in. This will be followed by a 'Learn more' link.">
       This is a supervised user managed by <ph name="CUSTODIAN_EMAIL">$1<ex>user@gmail.com</ex>.</ph>
     </message>