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

chromeos/dbus/fake_cryptohome_client.cc

Index: chromeos/dbus/fake_cryptohome_client.cc
diff --git a/chromeos/dbus/fake_cryptohome_client.cc b/chromeos/dbus/fake_cryptohome_client.cc
index b678adabb01f154b526490c7ac6641b0012a2424..fc6562839de27e8b2c89930b442af1b445c48eb5 100644
--- a/chromeos/dbus/fake_cryptohome_client.cc
+++ b/chromeos/dbus/fake_cryptohome_client.cc
@@ -13,6 +13,7 @@
 #include "chromeos/chromeos_paths.h"
 #include "chromeos/dbus/cryptohome/key.pb.h"
 #include "chromeos/dbus/cryptohome/rpc.pb.h"
+#include "components/user_manager/user_id.h"
 #include "third_party/cros_system_api/dbus/service_constants.h"
 #include "third_party/protobuf/src/google/protobuf/io/coded_stream.h"
 #include "third_party/protobuf/src/google/protobuf/io/zero_copy_stream.h"
@@ -70,14 +71,14 @@ bool FakeCryptohomeClient::Unmount(bool* success) {
 }
 
 void FakeCryptohomeClient::AsyncCheckKey(
-    const std::string& username,
+    const user_manager::UserID& user_id,
     const std::string& key,
     const AsyncMethodCallback& callback) {
   ReturnAsyncMethodResult(callback, false);
 }
 
 void FakeCryptohomeClient::AsyncMigrateKey(
-    const std::string& username,
+    const user_manager::UserID& user_id,
     const std::string& from_key,
     const std::string& to_key,
     const AsyncMethodCallback& callback) {
@@ -85,7 +86,7 @@ void FakeCryptohomeClient::AsyncMigrateKey(
 }
 
 void FakeCryptohomeClient::AsyncRemove(
-    const std::string& username,
+    const user_manager::UserID& user_id,
     const AsyncMethodCallback& callback) {
   ReturnAsyncMethodResult(callback, false);
 }
@@ -98,22 +99,22 @@ void FakeCryptohomeClient::GetSystemSalt(
 }
 
 void FakeCryptohomeClient::GetSanitizedUsername(
-    const std::string& username,
+    const user_manager::UserID& user_id,
     const StringDBusMethodCallback& callback) {
   // Even for stub implementation we have to return different values so that
   // multi-profiles would work.
-  std::string sanitized_username = GetStubSanitizedUsername(username);
+  std::string sanitized_username = GetStubSanitizedUsername(user_id);
   base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(callback, DBUS_METHOD_CALL_SUCCESS, sanitized_username));
 }
 
 std::string FakeCryptohomeClient::BlockingGetSanitizedUsername(
-    const std::string& username) {
-  return GetStubSanitizedUsername(username);
+    const user_manager::UserID& user_id) {
+  return GetStubSanitizedUsername(user_id);
 }
 
-void FakeCryptohomeClient::AsyncMount(const std::string& username,
+void FakeCryptohomeClient::AsyncMount(const user_manager::UserID& user_id,
                                           const std::string& key,
                                           int flags,
                                           const AsyncMethodCallback& callback) {
@@ -121,7 +122,7 @@ void FakeCryptohomeClient::AsyncMount(const std::string& username,
 }
 
 void FakeCryptohomeClient::AsyncAddKey(
-    const std::string& username,
+    const user_manager::UserID& user_id,
     const std::string& key,
     const std::string& new_key,
     const AsyncMethodCallback& callback) {
@@ -225,7 +226,7 @@ void FakeCryptohomeClient::Pkcs11GetTpmTokenInfo(
 }
 
 void FakeCryptohomeClient::Pkcs11GetTpmTokenInfoForUser(
-    const std::string& username,
+    const user_manager::UserID& user_id,
     const Pkcs11GetTpmTokenInfoCallback& callback) {
   Pkcs11GetTpmTokenInfo(callback);
 }
@@ -357,7 +358,7 @@ void FakeCryptohomeClient::AsyncTpmAttestationEnroll(
 void FakeCryptohomeClient::AsyncTpmAttestationCreateCertRequest(
     chromeos::attestation::PrivacyCAType pca_type,
     attestation::AttestationCertificateProfile certificate_profile,
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     const std::string& request_origin,
     const AsyncMethodCallback& callback) {
   ReturnAsyncMethodResult(callback, true);
@@ -366,7 +367,7 @@ void FakeCryptohomeClient::AsyncTpmAttestationCreateCertRequest(
 void FakeCryptohomeClient::AsyncTpmAttestationFinishCertRequest(
     const std::string& pca_response,
     attestation::AttestationKeyType key_type,
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     const std::string& key_name,
     const AsyncMethodCallback& callback) {
   ReturnAsyncMethodResult(callback, true);
@@ -374,7 +375,7 @@ void FakeCryptohomeClient::AsyncTpmAttestationFinishCertRequest(
 
 void FakeCryptohomeClient::TpmAttestationDoesKeyExist(
     attestation::AttestationKeyType key_type,
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     const std::string& key_name,
     const BoolDBusMethodCallback& callback) {
   base::MessageLoop::current()->PostTask(
@@ -383,7 +384,7 @@ void FakeCryptohomeClient::TpmAttestationDoesKeyExist(
 
 void FakeCryptohomeClient::TpmAttestationGetCertificate(
     attestation::AttestationKeyType key_type,
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     const std::string& key_name,
     const DataMethodCallback& callback) {
   base::MessageLoop::current()->PostTask(
@@ -393,7 +394,7 @@ void FakeCryptohomeClient::TpmAttestationGetCertificate(
 
 void FakeCryptohomeClient::TpmAttestationGetPublicKey(
     attestation::AttestationKeyType key_type,
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     const std::string& key_name,
     const DataMethodCallback& callback) {
   base::MessageLoop::current()->PostTask(
@@ -403,7 +404,7 @@ void FakeCryptohomeClient::TpmAttestationGetPublicKey(
 
 void FakeCryptohomeClient::TpmAttestationRegisterKey(
     attestation::AttestationKeyType key_type,
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     const std::string& key_name,
     const AsyncMethodCallback& callback) {
   ReturnAsyncMethodResult(callback, true);
@@ -411,7 +412,7 @@ void FakeCryptohomeClient::TpmAttestationRegisterKey(
 
 void FakeCryptohomeClient::TpmAttestationSignEnterpriseChallenge(
     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,
@@ -423,7 +424,7 @@ void FakeCryptohomeClient::TpmAttestationSignEnterpriseChallenge(
 
 void FakeCryptohomeClient::TpmAttestationSignSimpleChallenge(
     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 AsyncMethodCallback& callback) {
@@ -432,7 +433,7 @@ void FakeCryptohomeClient::TpmAttestationSignSimpleChallenge(
 
 void FakeCryptohomeClient::TpmAttestationGetKeyPayload(
     attestation::AttestationKeyType key_type,
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     const std::string& key_name,
     const DataMethodCallback& callback) {
   base::MessageLoop::current()->PostTask(
@@ -442,7 +443,7 @@ void FakeCryptohomeClient::TpmAttestationGetKeyPayload(
 
 void FakeCryptohomeClient::TpmAttestationSetKeyPayload(
     attestation::AttestationKeyType key_type,
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     const std::string& key_name,
     const std::string& payload,
     const BoolDBusMethodCallback& callback) {
@@ -452,7 +453,7 @@ void FakeCryptohomeClient::TpmAttestationSetKeyPayload(
 
 void FakeCryptohomeClient::TpmAttestationDeleteKeys(
     attestation::AttestationKeyType key_type,
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     const std::string& key_prefix,
     const BoolDBusMethodCallback& callback) {
   base::MessageLoop::current()->PostTask(
@@ -486,7 +487,8 @@ void FakeCryptohomeClient::MountEx(
   cryptohome::BaseReply reply;
   cryptohome::MountReply* mount =
       reply.MutableExtension(cryptohome::MountReply::reply);
-  mount->set_sanitized_username(GetStubSanitizedUsername(id.email()));
+  const user_manager::UserID user_id(std::string() /* gaia_id */, id.email());
+  mount->set_sanitized_username(GetStubSanitizedUsername(user_id));
   ReturnProtobufMethodCallback(reply, callback);
 }