Revert of This CL replaces user_manager::UserID with AccountId.

ash/system/user/tray_user_unittest.cc

Index: ash/system/user/tray_user_unittest.cc
diff --git a/ash/system/user/tray_user_unittest.cc b/ash/system/user/tray_user_unittest.cc
index ee1a92aabcb0ab9e98dc49ada21e8d5365bf6c61..5d9d3d3ab9bc6ee74843aabc55f84bedf4aa4448 100644
--- a/ash/system/user/tray_user_unittest.cc
+++ b/ash/system/user/tray_user_unittest.cc
@@ -17,7 +17,6 @@
 #include "ash/test/test_session_state_delegate.h"
 #include "ash/test/test_shell_delegate.h"
 #include "base/strings/utf_string_conversions.h"
-#include "components/signin/core/account_id/account_id.h"
 #include "components/user_manager/user_info.h"
 #include "ui/accessibility/ax_view_state.h"
 #include "ui/events/test/event_generator.h"
@@ -273,11 +272,10 @@
   ClickUserItem(&generator, 1);
   const user_manager::UserInfo* active_user = delegate()->GetActiveUserInfo();
   const user_manager::UserInfo* second_user = delegate()->GetUserInfo(1);
-  EXPECT_EQ(active_user->GetAccountId(), second_user->GetAccountId());
+  EXPECT_EQ(active_user->GetUserID(), second_user->GetUserID());
   // Since the name is capitalized, the email should be different then the
   // user_id.
-  EXPECT_NE(active_user->GetAccountId().GetUserEmail(),
-            second_user->GetEmail());
+  EXPECT_NE(active_user->GetUserID(), second_user->GetEmail());
   tray()->CloseSystemBubble();
 }