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

chrome/browser/chromeos/login/saml/saml_browsertest.cc

 // Copyright 2014 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 <cstring>
 #include <string>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 262 matching lines @@
 
   return std::move(http_response);
 }
 
 // A FakeCryptohomeClient that stores the salted and hashed secret passed to
 // MountEx().
 class SecretInterceptingFakeCryptohomeClient : public FakeCryptohomeClient {
  public:
   SecretInterceptingFakeCryptohomeClient();
 
-  void MountEx(const cryptohome::AccountIdentifier& id,
+  void MountEx(const cryptohome::Identification& id,
                const cryptohome::AuthorizationRequest& auth,
                const cryptohome::MountRequest& request,
                const ProtobufMethodCallback& callback) override;
 
   const std::string& salted_hashed_secret() { return salted_hashed_secret_; }
 
  private:
   std::string salted_hashed_secret_;
 
   DISALLOW_COPY_AND_ASSIGN(SecretInterceptingFakeCryptohomeClient);
 };
 
 SecretInterceptingFakeCryptohomeClient::
     SecretInterceptingFakeCryptohomeClient() {
 }
 
 void SecretInterceptingFakeCryptohomeClient::MountEx(
-    const cryptohome::AccountIdentifier& id,
+    const cryptohome::Identification& id,
     const cryptohome::AuthorizationRequest& auth,
     const cryptohome::MountRequest& request,
     const ProtobufMethodCallback& callback) {
   salted_hashed_secret_ = auth.key().secret();
   FakeCryptohomeClient::MountEx(id, auth, request, callback);
 }
 
 }  // namespace
 
 class SamlTest : public OobeBaseTest {
@@ skipping 922 matching lines @@
                 kTestAuthLSIDCookie1);
 
   GetCookies();
   EXPECT_EQ(kTestAuthSIDCookie1, GetCookieValue(kGAIASIDCookieName));
   EXPECT_EQ(kTestAuthLSIDCookie1, GetCookieValue(kGAIALSIDCookieName));
   EXPECT_EQ(kSAMLIdPCookieValue1, GetCookieValue(kSAMLIdPCookieName));
 }
 
 
 }  // namespace chromeos