ChromeOS cryptohome should be able to use gaia id as user identifier.

chromeos/attestation/mock_attestation_flow.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_ATTESTATION_MOCK_ATTESTATION_FLOW_H_
 #define CHROMEOS_ATTESTATION_MOCK_ATTESTATION_FLOW_H_
 
 #include "chromeos/attestation/attestation_flow.h"
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
+class AccountId;
+
 namespace chromeos {
 namespace attestation {
 
 // A fake server proxy which just appends "_response" to every request.
 class FakeServerProxy : public ServerProxy {
  public:
   FakeServerProxy();
   ~FakeServerProxy() override;
 
   void set_result(bool result) {
@@ skipping 35 matching lines @@
   virtual ~MockObserver();
 
   MOCK_METHOD2(MockCertificateCallback, void(bool, const std::string&));
 };
 
 class MockAttestationFlow : public AttestationFlow {
  public:
   MockAttestationFlow();
   virtual ~MockAttestationFlow();
 
-  MOCK_METHOD5(GetCertificate, void(AttestationCertificateProfile,
-                                    const std::string&,
-                                    const std::string&,
-                                    bool,
-                                    const CertificateCallback&));
+  MOCK_METHOD5(GetCertificate,
+               void(AttestationCertificateProfile,
+                    const AccountId& account_id,
+                    const std::string&,
+                    bool,
+                    const CertificateCallback&));
 };
 
 }  // namespace attestation
 }  // namespace chromeos
 
 #endif  // CHROMEOS_ATTESTATION_MOCK_ATTESTATION_FLOW_H_