Correctly deal with tokens for supervised users in ProfileOAuth2TokenService.

chrome/browser/policy/cloud/user_policy_signin_service.cc

Index: chrome/browser/policy/cloud/user_policy_signin_service.cc
diff --git a/chrome/browser/policy/cloud/user_policy_signin_service.cc b/chrome/browser/policy/cloud/user_policy_signin_service.cc
index db1349a20a46a9a19bff7bec477954537f7dcb22..0aa6f2c05953f14849aaa0a0bcd5fd0a93960bbc 100644
--- a/chrome/browser/policy/cloud/user_policy_signin_service.cc
+++ b/chrome/browser/policy/cloud/user_policy_signin_service.cc
@@ -112,8 +112,11 @@ void UserPolicySigninService::OnRefreshTokenAvailable(
   }
 
   std::string username = GetSigninManager()->GetAuthenticatedUsername();
-  // Should not have OAuth tokens if the user isn't signed in.
-  DCHECK(!username.empty());
+
+  // Ignore OAuth tokens if the user isn't signed in.
+  if (username.empty())
+    return;
+
   // ProfileOAuth2TokenService now has a refresh token so initialize the
   // UserCloudPolicyManager.
   InitializeForSignedInUser(username);