We should use UserID object to identify users instead of username.

components/policy/core/browser/browser_policy_connector.h

Index: components/policy/core/browser/browser_policy_connector.h
diff --git a/components/policy/core/browser/browser_policy_connector.h b/components/policy/core/browser/browser_policy_connector.h
index 2c4307d3f711259ac557d154a1ba59a60f3b9a3f..bc270414a05b3bfb59faec1a60e6c0ebf29d24d1 100644
--- a/components/policy/core/browser/browser_policy_connector.h
+++ b/components/policy/core/browser/browser_policy_connector.h
@@ -23,6 +23,10 @@ namespace net {
 class URLRequestContextGetter;
 }
 
+namespace user_manager {
+class UserID;
+}
+
 namespace policy {
 
 class ConfigurationPolicyProvider;
@@ -90,8 +94,8 @@ class POLICY_EXPORT BrowserPolicyConnector {
 
   // Check whether a user is known to be non-enterprise. Domains such as
   // gmail.com and googlemail.com are known to not be managed. Also returns
-  // false if the username is empty.
-  static bool IsNonEnterpriseUser(const std::string& username);
+  // false if the user email is empty.
+  static bool IsNonEnterpriseUser(const user_manager::UserID& user_id);
 
   // Returns the URL for the device management service endpoint.
   static std::string GetDeviceManagementUrl();