Update TaskTraits in user_session_manager.cc.

chrome/browser/chromeos/login/session/user_session_manager.cc

Index: chrome/browser/chromeos/login/session/user_session_manager.cc
diff --git a/chrome/browser/chromeos/login/session/user_session_manager.cc b/chrome/browser/chromeos/login/session/user_session_manager.cc
index 581a1c197f8c69690c52a1cb8b5db8e9b90ef38f..62110ecb7f64ffc9ef5fa78079112bdaa68784fe 100644
--- a/chrome/browser/chromeos/login/session/user_session_manager.cc
+++ b/chrome/browser/chromeos/login/session/user_session_manager.cc
@@ -568,7 +568,7 @@ void UserSessionManager::InitRlz(Profile* profile) {
                      .WithShutdownBehavior(
                          base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN)
                      .WithPriority(base::TaskPriority::BACKGROUND)
-                     .WithFileIO(),
+                     .MayBlock(),
       base::Bind(&base::PathExists, GetRlzDisabledFlagPath()),
       base::Bind(&UserSessionManager::InitRlzImpl, AsWeakPtr(), profile));
 #endif