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

chromeos/cryptohome/async_method_caller.h

Index: chromeos/cryptohome/async_method_caller.h
diff --git a/chromeos/cryptohome/async_method_caller.h b/chromeos/cryptohome/async_method_caller.h
index 7f1660e4883cd8d22075283c94ffa41f1778327b..759afdb73121a12c23a1c75151e9764d9f6634d4 100644
--- a/chromeos/cryptohome/async_method_caller.h
+++ b/chromeos/cryptohome/async_method_caller.h
@@ -14,6 +14,10 @@
 #include "chromeos/dbus/cryptohome_client.h"
 #include "third_party/cros_system_api/dbus/service_constants.h"
 
+namespace user_manager {
+class UserID;
+} // namespace user_manager
+
 namespace cryptohome {
 
 // Note: This file is placed in ::cryptohome instead of ::chromeos::cryptohome
@@ -41,45 +45,45 @@ class CHROMEOS_EXPORT AsyncMethodCaller {
   virtual ~AsyncMethodCaller() {}
 
   // Asks cryptohomed to asynchronously try to find the cryptohome for
-  // |user_email| and then use |passhash| to unlock the key.
+  // |user_id| and then use |passhash| to unlock the key.
   // |callback| will be called with status info on completion.
-  virtual void AsyncCheckKey(const std::string& user_email,
+  virtual void AsyncCheckKey(const user_manager::UserID& user_id,
                              const std::string& passhash,
                              Callback callback) = 0;
 
   // Asks cryptohomed to asynchronously try to find the cryptohome for
-  // |user_email| and then change from using |old_hash| to lock the
+  // |user_id| and then change from using |old_hash| to lock the
   // key to using |new_hash|.
   // |callback| will be called with status info on completion.
-  virtual void AsyncMigrateKey(const std::string& user_email,
+  virtual void AsyncMigrateKey(const user_manager::UserID& user_id,
                                const std::string& old_hash,
                                const std::string& new_hash,
                                Callback callback) = 0;
 
   // Asks cryptohomed to asynchronously try to find the cryptohome for
-  // |user_email| and then mount it using |passhash| to unlock the key.
+  // |user_id| and then mount it using |passhash| to unlock the key.
   // The |flags| are a combination of |MountFlags|:
   // * CREATE_IF_MISSING Controls whether or not cryptohomed is asked to create
   //                     a new cryptohome if one does not exist yet for
-  //                     |user_email|.
+  //                     |user_id|.
   // * ENSURE_EPHEMERAL  If |true|, the mounted cryptohome will be backed by
   //                     tmpfs. If |false|, the ephemeral users policy decides
   //                     whether tmpfs or an encrypted directory is used as the
   //                     backend.
   // |callback| will be called with status info on completion.
   // If the |CREATE_IF_MISSING| flag is not given and no cryptohome exists
-  // for |user_email|, the expected result is
+  // for |user_id|, the expected result is
   // callback.Run(false, kCryptohomeMountErrorUserDoesNotExist). Otherwise,
   // the normal range of return codes is expected.
-  virtual void AsyncMount(const std::string& user_email,
+  virtual void AsyncMount(const user_manager::UserID& user_id,
                           const std::string& passhash,
                           int flags,
                           Callback callback) = 0;
 
   // Asks cryptohomed to asynchronously try to add another |new_passhash| for
-  // |user_email| using |passhash| to unlock the key.
+  // |user_id| using |passhash| to unlock the key.
   // |callback| will be called with status info on completion.
-  virtual void AsyncAddKey(const std::string& user_email,
+  virtual void AsyncAddKey(const user_manager::UserID& user_id,
                            const std::string& passhash,
                            const std::string& new_passhash,
                            Callback callback) = 0;
@@ -97,8 +101,8 @@ class CHROMEOS_EXPORT AsyncMethodCaller {
                                 Callback callback) = 0;
 
   // Asks cryptohomed to asynchronously try to find the cryptohome for
-  // |user_email| and then nuke it.
-  virtual void AsyncRemove(const std::string& user_email,
+  // |user_id| and then nuke it.
+  virtual void AsyncRemove(const user_manager::UserID& user_id,
                            Callback callback) = 0;
 
   // Asks cryptohomed to asynchronously create an attestation enrollment
@@ -126,7 +130,7 @@ class CHROMEOS_EXPORT AsyncMethodCaller {
   virtual void AsyncTpmAttestationCreateCertRequest(
       chromeos::attestation::PrivacyCAType pca_type,
       chromeos::attestation::AttestationCertificateProfile certificate_profile,
-      const std::string& user_id,
+      const user_manager::UserID& user_id,
       const std::string& request_origin,
       const DataCallback& callback) = 0;
 
@@ -136,22 +140,20 @@ class CHROMEOS_EXPORT AsyncMethodCaller {
   // emitted by the Privacy CA.  |key_type| determines whether the certified key
   // is to be associated with the current user.  |key_name| is a name for the
   // key.  If |key_type| is KEY_USER, a |user_id| must be provided.  Otherwise
-  // |user_id| is ignored.  For normal GAIA users the |user_id| is a canonical
-  // email address.
+  // |user_id| is ignored.
   virtual void AsyncTpmAttestationFinishCertRequest(
       const std::string& pca_response,
       chromeos::attestation::AttestationKeyType key_type,
-      const std::string& user_id,
+      const user_manager::UserID& user_id,
       const std::string& key_name,
       const DataCallback& callback) = 0;
 
   // Asks cryptohomed to asynchronously register the attestation key specified
   // by |key_type| and |key_name|.  If |key_type| is KEY_USER, a |user_id| must
-  // be provided.  Otherwise |user_id| is ignored.  For normal GAIA users the
-  // |user_id| is a canonical email address.
+  // be provided.  Otherwise |user_id| is ignored.
   virtual void TpmAttestationRegisterKey(
       chromeos::attestation::AttestationKeyType key_type,
-      const std::string& user_id,
+      const user_manager::UserID& user_id,
       const std::string& key_name,
       const Callback& callback) = 0;
 
@@ -160,11 +162,10 @@ class CHROMEOS_EXPORT AsyncMethodCaller {
   // parameters will be included in the challenge response.  |challenge| must be
   // a valid enterprise challenge.  On success, the data sent to |callback| is
   // the challenge response.  If |key_type| is KEY_USER, a |user_id| must be
-  // provided.  Otherwise |user_id| is ignored.  For normal GAIA users the
-  // |user_id| is a canonical email address.
+  // provided.  Otherwise |user_id| is ignored.
   virtual void TpmAttestationSignEnterpriseChallenge(
       chromeos::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,
@@ -176,20 +177,19 @@ class CHROMEOS_EXPORT AsyncMethodCaller {
   // specified by |key_type| and |key_name|.  |challenge| can be any arbitrary
   // set of bytes.  On success, the data sent to |callback| is the challenge
   // response.  If |key_type| is KEY_USER, a |user_id| must be provided.
-  // Otherwise |user_id| is ignored.  For normal GAIA users the |user_id| is a
-  // canonical email address.
+  // Otherwise |user_id| is ignored.
   virtual void TpmAttestationSignSimpleChallenge(
       chromeos::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 DataCallback& callback) = 0;
 
   // Asks cryptohome to asynchronously retrieve a string associated with given
-  // |user| that would be used in mount path instead of |user|.
+  // |user_id| that would be used in mount path instead of |user|.
   // On success the data is sent to |callback|.
   virtual void AsyncGetSanitizedUsername(
-      const std::string& user,
+      const user_manager::UserID& user_id,
       const DataCallback& callback) = 0;
 
   // Creates the global AsyncMethodCaller instance.