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

chrome/browser/chromeos/policy/user_cloud_policy_store_chromeos.cc

Index: chrome/browser/chromeos/policy/user_cloud_policy_store_chromeos.cc
diff --git a/chrome/browser/chromeos/policy/user_cloud_policy_store_chromeos.cc b/chrome/browser/chromeos/policy/user_cloud_policy_store_chromeos.cc
index 43b72890b144aaf3e8df9b175a1362166c39dd8a..ba548ad7883954f429fb7bc55938fd8dc9457ce0 100644
--- a/chrome/browser/chromeos/policy/user_cloud_policy_store_chromeos.cc
+++ b/chrome/browser/chromeos/policy/user_cloud_policy_store_chromeos.cc
@@ -49,9 +49,9 @@ void SampleValidationFailure(ValidationFailure sample) {
                             VALIDATION_FAILURE_SIZE);
 }
 
-// Extracts the domain name from the passed username.
-std::string ExtractDomain(const std::string& username) {
-  return gaia::ExtractDomainName(gaia::CanonicalizeEmail(username));
+// Extracts the domain name from the passed user_email.
+std::string ExtractDomain(const std::string& user_email) {
+  return gaia::ExtractDomainName(gaia::CanonicalizeEmail(user_email));
 }
 
 }  // namespace
@@ -174,14 +174,14 @@ UserCloudPolicyStoreChromeOS::UserCloudPolicyStoreChromeOS(
     chromeos::CryptohomeClient* cryptohome_client,
     chromeos::SessionManagerClient* session_manager_client,
     scoped_refptr<base::SequencedTaskRunner> background_task_runner,
-    const std::string& username,
+    const user_manager::UserID& user_id,
     const base::FilePath& user_policy_key_dir,
     const base::FilePath& legacy_token_cache_file,
     const base::FilePath& legacy_policy_cache_file)
     : UserCloudPolicyStoreBase(background_task_runner),
       cryptohome_client_(cryptohome_client),
       session_manager_client_(session_manager_client),
-      username_(username),
+      user_id_(user_id),
       user_policy_key_dir_(user_policy_key_dir),
       legacy_cache_dir_(legacy_token_cache_file.DirName()),
       legacy_loader_(new LegacyPolicyCacheLoader(legacy_token_cache_file,
@@ -209,7 +209,7 @@ void UserCloudPolicyStoreChromeOS::Load() {
   // Cancel all pending requests.
   weak_factory_.InvalidateWeakPtrs();
   session_manager_client_->RetrievePolicyForUser(
-      username_,
+      user_id_,
       base::Bind(&UserCloudPolicyStoreChromeOS::OnPolicyRetrieved,
                  weak_factory_.GetWeakPtr()));
 }
@@ -224,7 +224,7 @@ void UserCloudPolicyStoreChromeOS::LoadImmediately() {
   // Profile initialization never sees unmanaged prefs, which would lead to
   // data loss. http://crbug.com/263061
   std::string policy_blob =
-      session_manager_client_->BlockingRetrievePolicyForUser(username_);
+      session_manager_client_->BlockingRetrievePolicyForUser(user_id_);
   if (policy_blob.empty()) {
     // The session manager doesn't have policy, or the call failed.
     // Just notify that the load is done, and don't bother with the legacy
@@ -241,7 +241,7 @@ void UserCloudPolicyStoreChromeOS::LoadImmediately() {
   }
 
   std::string sanitized_username =
-      cryptohome_client_->BlockingGetSanitizedUsername(username_);
+      cryptohome_client_->BlockingGetSanitizedUsername(user_id_);
   if (sanitized_username.empty()) {
     status_ = STATUS_LOAD_ERROR;
     NotifyStoreError();
@@ -265,15 +265,15 @@ void UserCloudPolicyStoreChromeOS::ValidatePolicyForStore(
   scoped_ptr<UserCloudPolicyValidator> validator =
       CreateValidator(policy.Pass(),
                       CloudPolicyValidatorBase::TIMESTAMP_REQUIRED);
-  validator->ValidateUsername(username_, true);
+  validator->ValidateUsername(user_id_, true);
   if (policy_key_.empty()) {
     validator->ValidateInitialKey(GetPolicyVerificationKey(),
-                                  ExtractDomain(username_));
+                                  ExtractDomain(user_id_.GetUserEmail()));
   } else {
     const bool allow_rotation = true;
     validator->ValidateSignature(policy_key_,
                                  GetPolicyVerificationKey(),
-                                 ExtractDomain(username_),
+                                 ExtractDomain(user_id_.GetUserEmail()),
                                  allow_rotation);
   }
 
@@ -307,7 +307,7 @@ void UserCloudPolicyStoreChromeOS::OnPolicyToStoreValidated(
   }
 
   session_manager_client_->StorePolicyForUser(
-      username_,
+      user_id_,
       policy_blob,
       base::Bind(&UserCloudPolicyStoreChromeOS::OnPolicyStored,
                  weak_factory_.GetWeakPtr()));
@@ -415,7 +415,7 @@ void UserCloudPolicyStoreChromeOS::OnLegacyLoadFinished(
     scoped_ptr<UserCloudPolicyValidator> validator =
         CreateValidator(policy.Pass(),
                         CloudPolicyValidatorBase::TIMESTAMP_REQUIRED);
-    validator->ValidateUsername(username_, true);
+    validator->ValidateUsername(user_id_, true);
     validator.release()->StartValidation(
         base::Bind(&UserCloudPolicyStoreChromeOS::OnLegacyPolicyValidated,
                    weak_factory_.GetWeakPtr(),
@@ -527,7 +527,7 @@ void UserCloudPolicyStoreChromeOS::EnsurePolicyKeyLoaded(
   } else {
     // Get the hashed username that's part of the key's path, to determine
     // |policy_key_path_|.
-    cryptohome_client_->GetSanitizedUsername(username_,
+    cryptohome_client_->GetSanitizedUsername(user_id_,
         base::Bind(&UserCloudPolicyStoreChromeOS::OnGetSanitizedUsername,
                    weak_factory_.GetWeakPtr(),
                    callback));
@@ -554,7 +554,7 @@ UserCloudPolicyStoreChromeOS::CreateValidatorForLoad(
     scoped_ptr<em::PolicyFetchResponse> policy) {
   scoped_ptr<UserCloudPolicyValidator> validator = CreateValidator(
       policy.Pass(), CloudPolicyValidatorBase::TIMESTAMP_NOT_BEFORE);
-  validator->ValidateUsername(username_, true);
+  validator->ValidateUsername(user_id_, true);
   const bool allow_rotation = false;
   const std::string empty_key = std::string();
   // The policy loaded from session manager need not be validated using the
@@ -562,7 +562,7 @@ UserCloudPolicyStoreChromeOS::CreateValidatorForLoad(
   // data that was stored without a verification key. Hence passing an empty
   // value for the verification key.
   validator->ValidateSignature(
-      policy_key_, empty_key, ExtractDomain(username_), allow_rotation);
+      policy_key_, empty_key, ExtractDomain(user_id_.GetUserEmail()), allow_rotation);
   return validator.Pass();
 }
 }  // namespace policy