This CL replaces user_manager::UserID with AccountId.

chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager_policy_browsertest.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 <string>
 #include <vector>
 
 #include "ash/desktop_background/desktop_background_controller.h"
 #include "ash/desktop_background/desktop_background_controller_observer.h"
 #include "ash/shell.h"
@@ skipping 226 matching lines @@
     policy::UserPolicyBuilder* builder =
         user_policy_builders_[user_number].get();
     if (!filename.empty()) {
       builder->payload().
           mutable_wallpaperimage()->set_value(ConstructPolicy(filename));
     } else {
       builder->payload().Clear();
     }
     builder->Build();
     fake_session_manager_client_->set_user_policy(user_id, builder->GetBlob());
-    const user_manager::User* user =
-        user_manager::UserManager::Get()->FindUser(user_id);
+    const user_manager::User* user = user_manager::UserManager::Get()->FindUser(
+        AccountId::FromUserEmail(user_id));
     ASSERT_TRUE(user);
     policy::CloudPolicyStore* store = GetStoreForUser(user);
     ASSERT_TRUE(store);
     store->Load();
     ASSERT_EQ(policy::CloudPolicyStore::STATUS_OK, store->status());
     ASSERT_EQ(policy::CloudPolicyValidatorBase::VALIDATION_OK,
               store->validation_status());
   }
 
   // Obtain WallpaperInfo for |user_number| from WallpaperManager.
@@ skipping 140 matching lines @@
 
 IN_PROC_BROWSER_TEST_F(WallpaperManagerPolicyTest, PersistOverLogout) {
   LoginUser(testUsers_[0]);
 
   // Wait until wallpaper has been loaded.
   RunUntilWallpaperChangeCount(1);
   ASSERT_EQ(kRedImageColor, GetAverageBackgroundColor());
 }
 
 }  // namespace chromeos