Tame the proliferation of UserContext constructors

chrome/browser/managed_mode/chromeos/manager_password_service.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 "chrome/browser/managed_mode/chromeos/manager_password_service.h"
 
 #include "base/bind.h"
 #include "base/metrics/histogram.h"
 #include "base/values.h"
 #include "chrome/browser/chromeos/login/managed/locally_managed_user_constants.h"
@@ skipping 109 matching lines @@
                                &encryption_key)) {
     LOG(WARNING) << "Can not apply password change to " << user_id
                  << ": no signature / encryption keys.";
     UMA_HISTOGRAM_ENUMERATION(
         "ManagedUsers.ChromeOS.PasswordChange",
         SupervisedUserAuthentication::PASSWORD_CHANGE_FAILED_NO_SIGNATURE_KEY,
         SupervisedUserAuthentication::PASSWORD_CHANGE_RESULT_MAX_VALUE);
     return;
   }
 
-  UserContext manager_key(user_id, master_key, std::string());
+  UserContext manager_key(user_id);
+  manager_key.SetPassword(master_key);
   manager_key.SetIsUsingOAuth(false);
 
   // As master key can have old label, leave label field empty - it will work
   // as wildcard.
 
   std::string new_key;
   int revision;
 
   bool has_data = password_data->GetStringWithoutPathExpansion(
       kEncryptedPassword, &new_key);
@@ skipping 68 matching lines @@
   }
 }
 
 void ManagerPasswordService::OnContextTransformed(
     const UserContext& master_key_context) {
   DCHECK(!master_key_context.DoesNeedPasswordHashing());
   cryptohome::KeyDefinition new_master_key(master_key_context.GetPassword(),
                                            kCryptohomeMasterKeyLabel,
                                            cryptohome::PRIV_DEFAULT);
   // Use new master key for further actions.
-  UserContext new_master_key_context;
-  new_master_key_context.CopyFrom(master_key_context);
+  UserContext new_master_key_context = master_key_context;
   new_master_key_context.SetKeyLabel(kCryptohomeMasterKeyLabel);
   authenticator_->AddKey(
       master_key_context,
       new_master_key,
       true /* replace existing */,
       base::Bind(&ManagerPasswordService::OnNewManagerKeySuccess,
                  weak_ptr_factory_.GetWeakPtr(),
                  new_master_key_context));
 }
 
@@ skipping 23 matching lines @@
 void ManagerPasswordService::OnOldManagerKeyDeleted(
     const UserContext& master_key_context) {
   VLOG(1) << "Removed old master key for " << master_key_context.GetUserID();
 }
 
 void ManagerPasswordService::Shutdown() {
   settings_service_subscription_.reset();
 }
 
 }  // namespace chromeos