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

chromeos/cryptohome/mock_async_method_caller.h

 // Copyright (c) 2012 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_CRYPTOHOME_MOCK_ASYNC_METHOD_CALLER_H_
 #define CHROMEOS_CRYPTOHOME_MOCK_ASYNC_METHOD_CALLER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "chromeos/cryptohome/async_method_caller.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace cryptohome {
 
 class MockAsyncMethodCaller : public AsyncMethodCaller {
  public:
   static const char kFakeAttestationEnrollRequest[];
   static const char kFakeAttestationCertRequest[];
   static const char kFakeAttestationCert[];
   static const char kFakeSanitizedUsername[];
   static const char kFakeChallengeResponse[];
 
   MockAsyncMethodCaller();
   virtual ~MockAsyncMethodCaller();
 
   void SetUp(bool success, MountError return_code);
 
-  MOCK_METHOD3(AsyncCheckKey, void(const std::string& user_email,
+  MOCK_METHOD3(AsyncCheckKey, void(const user_manager::UserID& user_id,
                                    const std::string& passhash,
                                    Callback callback));
-  MOCK_METHOD4(AsyncMigrateKey, void(const std::string& user_email,
+  MOCK_METHOD4(AsyncMigrateKey, void(const user_manager::UserID& user_id,
                                      const std::string& old_hash,
                                      const std::string& new_hash,
                                      Callback callback));
-  MOCK_METHOD4(AsyncMount, void(const std::string& user_email,
+  MOCK_METHOD4(AsyncMount, void(const user_manager::UserID& user_id,
                                 const std::string& passhash,
                                 int flags,
                                 Callback callback));
-  MOCK_METHOD4(AsyncAddKey, void(const std::string& user_email,
+  MOCK_METHOD4(AsyncAddKey, void(const user_manager::UserID& user_id,
                                  const std::string& passhash,
                                  const std::string& new_key,
                                  Callback callback));
   MOCK_METHOD1(AsyncMountGuest, void(Callback callback));
   MOCK_METHOD3(AsyncMountPublic, void(const std::string& public_mount_id,
                                       int flags,
                                       Callback callback));
-  MOCK_METHOD2(AsyncRemove, void(const std::string& user_email,
+  MOCK_METHOD2(AsyncRemove, void(const user_manager::UserID& user_id,
                                  Callback callback));
   MOCK_METHOD2(AsyncTpmAttestationCreateEnrollRequest,
                void(chromeos::attestation::PrivacyCAType pca_type,
                     const DataCallback& callback));
   MOCK_METHOD3(AsyncTpmAttestationEnroll,
                void(chromeos::attestation::PrivacyCAType pca_type,
                     const std::string& pca_response,
                     const Callback& callback));
   MOCK_METHOD5(
       AsyncTpmAttestationCreateCertRequest,
       void(chromeos::attestation::PrivacyCAType pca_type,
            chromeos::attestation::AttestationCertificateProfile profile,
-           const std::string& user_id,
+           const user_manager::UserID& user_id,
            const std::string& request_origin,
            const DataCallback& callback));
   MOCK_METHOD5(AsyncTpmAttestationFinishCertRequest,
                void(const std::string& pca_response,
                     chromeos::attestation::AttestationKeyType key_type,
-                    const std::string& user_id,
+                    const user_manager::UserID& user_id,
                     const std::string& key_name,
                     const DataCallback& callback));
   MOCK_METHOD4(TpmAttestationRegisterKey,
                void(chromeos::attestation::AttestationKeyType key_type,
-                    const std::string& user_id,
+                    const user_manager::UserID& user_id,
                     const std::string& key_name,
                     const Callback& callback));
   MOCK_METHOD8(
       TpmAttestationSignEnterpriseChallenge,
       void(chromeos::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,
            chromeos::attestation::AttestationChallengeOptions options,
            const std::string& challenge,
            const DataCallback& callback));
   MOCK_METHOD5(TpmAttestationSignSimpleChallenge,
                void(chromeos::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 DataCallback& callback));
   MOCK_METHOD2(AsyncGetSanitizedUsername,
-               void(const std::string& user,
+               void(const user_manager::UserID& user_id,
                     const DataCallback& callback));
 
  private:
   bool success_;
   MountError return_code_;
 
   void DoCallback(Callback callback);
   // Default fakes for attestation calls.
   void FakeCreateEnrollRequest(const DataCallback& callback);
   void FakeCreateCertRequest(const DataCallback& callback);
   void FakeFinishCertRequest(const DataCallback& callback);
   void FakeGetSanitizedUsername(const DataCallback& callback);
   void FakeEnterpriseChallenge(const DataCallback& callback);
 
   DISALLOW_COPY_AND_ASSIGN(MockAsyncMethodCaller);
 };
 
 }  // namespace cryptohome
 
 #endif  // CHROMEOS_CRYPTOHOME_MOCK_ASYNC_METHOD_CALLER_H_