This CL replaces std::string user_id in ash/* with AccountId.

chrome/browser/ui/ash/session_state_delegate_views.cc

 // Copyright (c) 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/ui/ash/session_state_delegate_views.h"
 
 #include "base/logging.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/user_manager/empty_user_info.h"
@@ skipping 53 matching lines @@
 
 bool SessionStateDelegate::ShouldShowAvatar(aura::Window* window) const {
   return false;
 }
 
 gfx::ImageSkia SessionStateDelegate::GetAvatarImageForWindow(
     aura::Window* window) const {
   return gfx::ImageSkia();
 }
 
-void SessionStateDelegate::SwitchActiveUser(const std::string& user_id) {
+void SessionStateDelegate::SwitchActiveUser(const AccountId& /* account_id*/) {
   NOTIMPLEMENTED();
 }
 
 void SessionStateDelegate::CycleActiveUser(CycleUser cycle_user) {
   NOTIMPLEMENTED();
 }
 
 bool SessionStateDelegate::IsMultiProfileAllowedByPrimaryUserPolicy() const {
   return true;
 }
 
 void SessionStateDelegate::AddSessionStateObserver(
     ash::SessionStateObserver* observer) {
   NOTIMPLEMENTED();
 }
 
 void SessionStateDelegate::RemoveSessionStateObserver(
     ash::SessionStateObserver* observer) {
   NOTIMPLEMENTED();
 }