This CL replaces user_manager::UserID with AccountId.

chrome/browser/chromeos/file_system_provider/mount_path_util_unittest.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/chromeos/file_system_provider/mount_path_util.h"
 
 #include <string>
 
 #include "base/files/file.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 52 matching lines @@
   FileSystemProviderMountPathUtilTest() {}
   ~FileSystemProviderMountPathUtilTest() override {}
 
   void SetUp() override {
     profile_manager_.reset(
         new TestingProfileManager(TestingBrowserProcess::GetGlobal()));
     ASSERT_TRUE(profile_manager_->SetUp());
     profile_ = profile_manager_->CreateTestingProfile("testing-profile");
     user_manager_ = new FakeChromeUserManager();
     user_manager_enabler_.reset(new ScopedUserManagerEnabler(user_manager_));
-    user_manager_->AddUser(profile_->GetProfileUserName());
+    user_manager_->AddUser(
+        AccountId::FromUserEmail(profile_->GetProfileUserName()));
     file_system_provider_service_ = Service::Get(profile_);
     file_system_provider_service_->SetFileSystemFactoryForTesting(
         base::Bind(&FakeProvidedFileSystem::Create));
   }
 
   content::TestBrowserThreadBundle thread_bundle_;
   scoped_ptr<TestingProfileManager> profile_manager_;
   TestingProfile* profile_;  // Owned by TestingProfileManager.
   scoped_ptr<ScopedUserManagerEnabler> user_manager_enabler_;
   FakeChromeUserManager* user_manager_;
@@ skipping 208 matching lines @@
     const base::FilePath kFilePath =
         base::FilePath(FILE_PATH_LITERAL("provided/hello/world"));
     LocalPathParser parser(profile_, kFilePath);
     EXPECT_FALSE(parser.Parse());
   }
 }
 
 }  // namespace util
 }  // namespace file_system_provider
 }  // namespace chromeos