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

chromeos/dbus/fake_cryptohome_client.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROMEOS_DBUS_FAKE_CRYPTOHOME_CLIENT_H_
 #define CHROMEOS_DBUS_FAKE_CRYPTOHOME_CLIENT_H_
 
 #include <map>
 
 #include "base/basictypes.h"
 #include "base/memory/weak_ptr.h"
 #include "chromeos/dbus/cryptohome_client.h"
 
 namespace chromeos {
 
 class CHROMEOS_EXPORT FakeCryptohomeClient : public CryptohomeClient {
  public:
   FakeCryptohomeClient();
   ~FakeCryptohomeClient() override;
 
   void Init(dbus::Bus* bus) override;
   void SetAsyncCallStatusHandlers(
       const AsyncCallStatusHandler& handler,
       const AsyncCallStatusWithDataHandler& data_handler) override;
   void ResetAsyncCallStatusHandlers() override;
   void WaitForServiceToBeAvailable(
       const WaitForServiceToBeAvailableCallback& callback) override;
   void IsMounted(const BoolDBusMethodCallback& callback) override;
   bool Unmount(bool* success) override;
-  void AsyncCheckKey(const std::string& username,
+  void AsyncCheckKey(const user_manager::UserID& user_id,
                      const std::string& key,
                      const AsyncMethodCallback& callback) override;
-  void AsyncMigrateKey(const std::string& username,
+  void AsyncMigrateKey(const user_manager::UserID& user_id,
                        const std::string& from_key,
                        const std::string& to_key,
                        const AsyncMethodCallback& callback) override;
-  void AsyncRemove(const std::string& username,
+  void AsyncRemove(const user_manager::UserID& user_id,
                    const AsyncMethodCallback& callback) override;
   void GetSystemSalt(const GetSystemSaltCallback& callback) override;
-  void GetSanitizedUsername(const std::string& username,
+  void GetSanitizedUsername(const user_manager::UserID& user_id,
                             const StringDBusMethodCallback& callback) override;
   std::string BlockingGetSanitizedUsername(
-      const std::string& username) override;
-  void AsyncMount(const std::string& username,
+      const user_manager::UserID& user_id) override;
+  void AsyncMount(const user_manager::UserID& user_id,
                   const std::string& key,
                   int flags,
                   const AsyncMethodCallback& callback) override;
-  void AsyncAddKey(const std::string& username,
+  void AsyncAddKey(const user_manager::UserID& user_id,
                    const std::string& key,
                    const std::string& new_key,
                    const AsyncMethodCallback& callback) override;
   void AsyncMountGuest(const AsyncMethodCallback& callback) override;
   void AsyncMountPublic(const std::string& public_mount_id,
                         int flags,
                         const AsyncMethodCallback& callback) override;
   void TpmIsReady(const BoolDBusMethodCallback& callback) override;
   void TpmIsEnabled(const BoolDBusMethodCallback& callback) override;
   bool CallTpmIsEnabledAndBlock(bool* enabled) override;
   void TpmGetPassword(const StringDBusMethodCallback& callback) override;
   void TpmIsOwned(const BoolDBusMethodCallback& callback) override;
   bool CallTpmIsOwnedAndBlock(bool* owned) override;
   void TpmIsBeingOwned(const BoolDBusMethodCallback& callback) override;
   bool CallTpmIsBeingOwnedAndBlock(bool* owning) override;
   void TpmCanAttemptOwnership(const VoidDBusMethodCallback& callback) override;
   void TpmClearStoredPassword(const VoidDBusMethodCallback& callback) override;
   bool CallTpmClearStoredPasswordAndBlock() override;
   void Pkcs11IsTpmTokenReady(const BoolDBusMethodCallback& callback) override;
   void Pkcs11GetTpmTokenInfo(
       const Pkcs11GetTpmTokenInfoCallback& callback) override;
   void Pkcs11GetTpmTokenInfoForUser(
-      const std::string& username,
+      const user_manager::UserID& user_id,
       const Pkcs11GetTpmTokenInfoCallback& callback) override;
   bool InstallAttributesGet(const std::string& name,
                             std::vector<uint8>* value,
                             bool* successful) override;
   bool InstallAttributesSet(const std::string& name,
                             const std::vector<uint8>& value,
                             bool* successful) override;
   bool InstallAttributesFinalize(bool* successful) override;
   void InstallAttributesIsReady(
       const BoolDBusMethodCallback& callback) override;
   bool InstallAttributesIsInvalid(bool* is_invalid) override;
   bool InstallAttributesIsFirstInstall(bool* is_first_install) override;
   void TpmAttestationIsPrepared(
       const BoolDBusMethodCallback& callback) override;
   void TpmAttestationIsEnrolled(
       const BoolDBusMethodCallback& callback) override;
   void AsyncTpmAttestationCreateEnrollRequest(
       chromeos::attestation::PrivacyCAType pca_type,
       const AsyncMethodCallback& callback) override;
   void AsyncTpmAttestationEnroll(chromeos::attestation::PrivacyCAType pca_type,
                                  const std::string& pca_response,
                                  const AsyncMethodCallback& callback) override;
   void AsyncTpmAttestationCreateCertRequest(
       chromeos::attestation::PrivacyCAType pca_type,
       attestation::AttestationCertificateProfile certificate_profile,
-      const std::string& user_id,
+      const user_manager::UserID& user_id,
       const std::string& request_origin,
       const AsyncMethodCallback& callback) override;
   void AsyncTpmAttestationFinishCertRequest(
       const std::string& pca_response,
       attestation::AttestationKeyType key_type,
-      const std::string& user_id,
+      const user_manager::UserID& user_id,
       const std::string& key_name,
       const AsyncMethodCallback& callback) override;
   void TpmAttestationDoesKeyExist(
       attestation::AttestationKeyType key_type,
-      const std::string& user_id,
+      const user_manager::UserID& user_id,
       const std::string& key_name,
       const BoolDBusMethodCallback& callback) override;
   void TpmAttestationGetCertificate(
       attestation::AttestationKeyType key_type,
-      const std::string& user_id,
+      const user_manager::UserID& user_id,
       const std::string& key_name,
       const DataMethodCallback& callback) override;
   void TpmAttestationGetPublicKey(attestation::AttestationKeyType key_type,
-                                  const std::string& user_id,
+                                  const user_manager::UserID& user_id,
                                   const std::string& key_name,
                                   const DataMethodCallback& callback) override;
   void TpmAttestationRegisterKey(attestation::AttestationKeyType key_type,
-                                 const std::string& user_id,
+                                 const user_manager::UserID& user_id,
                                  const std::string& key_name,
                                  const AsyncMethodCallback& callback) override;
   void TpmAttestationSignEnterpriseChallenge(
       attestation::AttestationKeyType key_type,
-      const std::string& user_id,
+      const user_manager::UserID& user_id,
       const std::string& key_name,
       const std::string& domain,
       const std::string& device_id,
       attestation::AttestationChallengeOptions options,
       const std::string& challenge,
       const AsyncMethodCallback& callback) override;
   void TpmAttestationSignSimpleChallenge(
       attestation::AttestationKeyType key_type,
-      const std::string& user_id,
+      const user_manager::UserID& user_id,
       const std::string& key_name,
       const std::string& challenge,
       const AsyncMethodCallback& callback) override;
   void TpmAttestationGetKeyPayload(attestation::AttestationKeyType key_type,
-                                   const std::string& user_id,
+                                   const user_manager::UserID& user_id,
                                    const std::string& key_name,
                                    const DataMethodCallback& callback) override;
   void TpmAttestationSetKeyPayload(
       attestation::AttestationKeyType key_type,
-      const std::string& user_id,
+      const user_manager::UserID& user_id,
       const std::string& key_name,
       const std::string& payload,
       const BoolDBusMethodCallback& callback) override;
   void TpmAttestationDeleteKeys(
       attestation::AttestationKeyType key_type,
-      const std::string& user_id,
+      const user_manager::UserID& user_id,
       const std::string& key_prefix,
       const BoolDBusMethodCallback& callback) override;
   void GetKeyDataEx(const cryptohome::AccountIdentifier& id,
                     const cryptohome::AuthorizationRequest& auth,
                     const cryptohome::GetKeyDataRequest& request,
                     const ProtobufMethodCallback& callback) override;
   void CheckKeyEx(const cryptohome::AccountIdentifier& id,
                   const cryptohome::AuthorizationRequest& auth,
                   const cryptohome::CheckKeyRequest& request,
                   const ProtobufMethodCallback& callback) override;
@@ skipping 69 matching lines @@
   std::map<std::string, std::vector<uint8> > install_attrs_;
   bool locked_;
   base::WeakPtrFactory<FakeCryptohomeClient> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeCryptohomeClient);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_FAKE_CRYPTOHOME_CLIENT_H_