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

chrome/browser/chromeos/attestation/platform_verification_flow.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 "chrome/browser/chromeos/attestation/platform_verification_flow.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "chrome/browser/chromeos/attestation/attestation_ca_client.h"
 #include "chrome/browser/chromeos/attestation/attestation_signed_data.pb.h"
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 #include "chrome/browser/media/protected_media_identifier_permission_context.h"
 #include "chrome/browser/media/protected_media_identifier_permission_context_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chromeos/attestation/attestation_flow.h"
 #include "chromeos/chromeos_switches.h"
 #include "chromeos/cryptohome/async_method_caller.h"
 #include "chromeos/dbus/cryptohome_client.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "components/content_settings/core/browser/host_content_settings_map.h"
 #include "components/content_settings/core/common/content_settings_pattern.h"
 #include "components/content_settings/core/common/permission_request_id.h"
 #include "components/user_manager/user.h"
+#include "components/user_manager/user_id.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/url_constants.h"
 #include "net/cert/x509_certificate.h"
 
 namespace {
@@ skipping 192 matching lines @@
   }
 
   // Permission allowed. Now proceed to get certificate.
   const user_manager::User* user = delegate_->GetUser(context.web_contents);
   if (!user) {
     ReportError(context.callback, INTERNAL_ERROR);
     LOG(ERROR) << "Profile does not map to a valid user.";
     return;
   }
 
-  GetCertificate(context, user->email(), false /* Don't force a new key */);
+  GetCertificate(context, user->GetUserID(), false /* Don't force a new key */);
 }
 
 void PlatformVerificationFlow::GetCertificate(const ChallengeContext& context,
-                                              const std::string& user_id,
+                                              const user_manager::UserID& user_id,
                                               bool force_new_key) {
   scoped_ptr<base::Timer> timer(new base::Timer(false,    // Don't retain.
                                                 false));  // Don't repeat.
   base::Closure timeout_callback = base::Bind(
       &PlatformVerificationFlow::OnCertificateTimeout,
       this,
       context);
   timer->Start(FROM_HERE, timeout_delay_, timeout_callback);
 
   AttestationFlow::CertificateCallback certificate_callback = base::Bind(
       &PlatformVerificationFlow::OnCertificateReady,
       this,
       context,
       user_id,
       base::Passed(&timer));
   attestation_flow_->GetCertificate(
       PROFILE_CONTENT_PROTECTION_CERTIFICATE,
       user_id,
       context.service_id,
       force_new_key,
       certificate_callback);
 }
 
 void PlatformVerificationFlow::OnCertificateReady(
     const ChallengeContext& context,
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     scoped_ptr<base::Timer> timer,
     bool operation_success,
     const std::string& certificate) {
   // Log failure before checking the timer so all failures are logged, even if
   // they took too long.
   if (!operation_success) {
     LOG(WARNING) << "PlatformVerificationFlow: Failed to certify platform.";
   }
   if (!timer->IsRunning()) {
     LOG(WARNING) << "PlatformVerificationFlow: Certificate ready but call has "
@@ skipping 77 matching lines @@
                                             certificate.length()));
   if (!x509.get() || x509->valid_expiry().is_null()) {
     LOG(WARNING) << "Failed to parse certificate, cannot check expiry.";
     return false;
   }
   return (base::Time::Now() > x509->valid_expiry());
 }
 
 }  // namespace attestation
 }  // namespace chromeos