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

chrome/browser/ui/browser_finder_chromeos_unittest.cc

 // Copyright (c) 2015 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/browser_finder.h"
 
 #include "chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.h"
 #include "chrome/browser/ui/ash/multi_user/multi_user_window_manager.h"
 #include "chrome/browser/ui/ash/multi_user/multi_user_window_manager_chromeos.h"
 #include "chrome/test/base/browser_with_test_window_test.h"
 #include "chrome/test/base/test_browser_window_aura.h"
 #include "chrome/test/base/testing_browser_process.h"
 #include "chrome/test/base/testing_profile_manager.h"
+#include "components/signin/core/account_id/account_id.h"
 
 namespace test {
 
 namespace {
 
 const char kTestAccount1[] = "user1@test.com";
 const char kTestAccount2[] = "user2@test.com";
 
 }  // namespace
 
 class BrowserFinderChromeOSTest : public BrowserWithTestWindowTest {
  protected:
   BrowserFinderChromeOSTest() : multi_user_window_manager_(nullptr) {}
 
   TestingProfile* CreateMultiUserProfile(const std::string& user_email) {
     TestingProfile* profile =
         profile_manager_->CreateTestingProfile(user_email);
     GetUserWindowManager()->AddUser(profile);
     return profile;
   }
 
   chrome::MultiUserWindowManagerChromeOS* GetUserWindowManager() {
     if (!multi_user_window_manager_) {
       multi_user_window_manager_ =
-          new chrome::MultiUserWindowManagerChromeOS(kTestAccount1);
+          new chrome::MultiUserWindowManagerChromeOS(test_account_id1_);
       multi_user_window_manager_->Init();
       chrome::MultiUserWindowManager::SetInstanceForTest(
           multi_user_window_manager_,
           chrome::MultiUserWindowManager::MULTI_PROFILE_MODE_SEPARATED);
     }
     return multi_user_window_manager_;
   }
 
+  AccountId test_account_id1_ = EmptyAccountId();
+  AccountId test_account_id2_ = EmptyAccountId();
+
  private:
   void SetUp() override {
     profile_manager_.reset(
         new TestingProfileManager(TestingBrowserProcess::GetGlobal()));
     ASSERT_TRUE(profile_manager_->SetUp());
+    test_account_id1_ = AccountId::FromUserEmail(kTestAccount1);
+    test_account_id2_ = AccountId::FromUserEmail(kTestAccount2);
     profile_manager_->SetLoggedIn(true);
     chromeos::WallpaperManager::Initialize();
     BrowserWithTestWindowTest::SetUp();
-    second_profile_ = CreateMultiUserProfile(kTestAccount2);
+    second_profile_ = CreateMultiUserProfile(test_account_id2_.GetUserEmail());
   }
 
   void TearDown() override {
     chrome::MultiUserWindowManager::DeleteInstance();
     BrowserWithTestWindowTest::TearDown();
     chromeos::WallpaperManager::Shutdown();
     if (second_profile_) {
       DestroyProfile(second_profile_);
       second_profile_ = nullptr;
     }
   }
 
   TestingProfile* CreateProfile() override {
-    return CreateMultiUserProfile(kTestAccount1);
+    return CreateMultiUserProfile(test_account_id1_.GetUserEmail());
   }
 
   void DestroyProfile(TestingProfile* test_profile) override {
     profile_manager_->DeleteTestingProfile(test_profile->GetProfileUserName());
   }
 
   TestingProfile* second_profile_;
   scoped_ptr<TestingProfileManager> profile_manager_;
   chrome::MultiUserWindowManagerChromeOS* multi_user_window_manager_;
 
@@ skipping 26 matching lines @@
 }
 
 TEST_F(BrowserFinderChromeOSTest, FindBrowserOwnedByAnotherProfile) {
   set_browser(nullptr);
 
   Browser::CreateParams params(profile()->GetOriginalProfile(),
                                chrome::HOST_DESKTOP_TYPE_ASH);
   scoped_ptr<Browser> browser(
       chrome::CreateBrowserWithAuraTestWindowForParams(nullptr, &params));
   GetUserWindowManager()->SetWindowOwner(browser->window()->GetNativeWindow(),
-                                         kTestAccount1);
+                                         test_account_id1_);
   EXPECT_EQ(1u,
             chrome::GetBrowserCount(profile(), chrome::HOST_DESKTOP_TYPE_ASH));
   EXPECT_TRUE(
       chrome::FindAnyBrowser(profile(), true, chrome::HOST_DESKTOP_TYPE_ASH));
   EXPECT_TRUE(
       chrome::FindAnyBrowser(profile(), false, chrome::HOST_DESKTOP_TYPE_ASH));
 
   // Move the browser window to another user's desktop. Then no window should
   // be available for the current profile.
   GetUserWindowManager()->ShowWindowForUser(
-      browser->window()->GetNativeWindow(), kTestAccount2);
+      browser->window()->GetNativeWindow(), test_account_id2_);
   EXPECT_EQ(0u,
             chrome::GetBrowserCount(profile(), chrome::HOST_DESKTOP_TYPE_ASH));
   EXPECT_FALSE(
       chrome::FindAnyBrowser(profile(), true, chrome::HOST_DESKTOP_TYPE_ASH));
   EXPECT_FALSE(
       chrome::FindAnyBrowser(profile(), false, chrome::HOST_DESKTOP_TYPE_ASH));
 }
 
 }  // namespace test