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

chromeos/cryptohome/mock_async_method_caller.h

Index: chromeos/cryptohome/mock_async_method_caller.h
diff --git a/chromeos/cryptohome/mock_async_method_caller.h b/chromeos/cryptohome/mock_async_method_caller.h
index 515ec780655f6112e0e6e11b6c4550436d6f8958..514ac705c78606bd3bf10d628e3adaec98d32289 100644
--- a/chromeos/cryptohome/mock_async_method_caller.h
+++ b/chromeos/cryptohome/mock_async_method_caller.h
@@ -27,18 +27,18 @@ class MockAsyncMethodCaller : public AsyncMethodCaller {
 
   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));
@@ -46,7 +46,7 @@ class MockAsyncMethodCaller : public AsyncMethodCaller {
   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,
@@ -59,24 +59,24 @@ class MockAsyncMethodCaller : public AsyncMethodCaller {
       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,
@@ -85,12 +85,12 @@ class MockAsyncMethodCaller : public AsyncMethodCaller {
            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: