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

chrome/browser/chromeos/attestation/platform_verification_flow_unittest.cc

 // 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.
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <string>
 
 #include "base/bind.h"
@@ skipping 146 matching lines @@
 
     settings_helper_.ReplaceProvider(kAttestationForContentProtectionEnabled);
     settings_helper_.SetBoolean(kAttestationForContentProtectionEnabled, true);
   }
 
   void ExpectAttestationFlow() {
     // When consent is not given or the feature is disabled, it is important
     // that there are no calls to the attestation service.  Thus, a test must
     // explicitly expect these calls or the mocks will fail the test.
 
+    const AccountId account_id = AccountId::FromUserEmail(kTestEmail);
     // Configure the mock AttestationFlow to call FakeGetCertificate.
     EXPECT_CALL(mock_attestation_flow_,
                 GetCertificate(PROFILE_CONTENT_PROTECTION_CERTIFICATE,
-                               kTestEmail, kTestID, _, _))
-        .WillRepeatedly(WithArgs<4>(Invoke(
-            this, &PlatformVerificationFlowTest::FakeGetCertificate)));
+                               account_id, kTestID, _, _))
+        .WillRepeatedly(WithArgs<4>(
+            Invoke(this, &PlatformVerificationFlowTest::FakeGetCertificate)));
 
     // Configure the mock AsyncMethodCaller to call FakeSignChallenge.
     std::string expected_key_name = std::string(kContentProtectionKeyPrefix) +
                                     std::string(kTestID);
     EXPECT_CALL(mock_async_caller_,
-                TpmAttestationSignSimpleChallenge(KEY_USER, kTestEmail,
-                                                  expected_key_name,
-                                                  kTestChallenge, _))
-        .WillRepeatedly(WithArgs<4>(Invoke(
-            this, &PlatformVerificationFlowTest::FakeSignChallenge)));
+                TpmAttestationSignSimpleChallenge(
+                    KEY_USER, cryptohome::Identification(account_id),
+                    expected_key_name, kTestChallenge, _))
+        .WillRepeatedly(WithArgs<4>(
+            Invoke(this, &PlatformVerificationFlowTest::FakeSignChallenge)));
   }
 
   void FakeGetCertificate(
       const AttestationFlow::CertificateCallback& callback) {
     std::string certificate =
         (fake_certificate_index_ < fake_certificate_list_.size()) ?
             fake_certificate_list_[fake_certificate_index_] : kTestCertificate;
     base::MessageLoop::current()->PostTask(FROM_HERE,
                                            base::Bind(callback,
                                                       certificate_success_,
@@ skipping 209 matching lines @@
 TEST_F(PlatformVerificationFlowTest, AttestationNotPrepared) {
   fake_cryptohome_client_.set_attestation_enrolled(false);
   fake_cryptohome_client_.set_attestation_prepared(false);
   verifier_->ChallengePlatformKey(NULL, kTestID, kTestChallenge, callback_);
   base::RunLoop().RunUntilIdle();
   EXPECT_EQ(PlatformVerificationFlow::PLATFORM_NOT_VERIFIED, result_);
 }
 
 }  // namespace attestation
 }  // namespace chromeos