Migrate base::TaskRunner from Closure to OnceClosure

chrome/browser/chromeos/login/users/mock_user_manager.cc

Index: chrome/browser/chromeos/login/users/mock_user_manager.cc
diff --git a/chrome/browser/chromeos/login/users/mock_user_manager.cc b/chrome/browser/chromeos/login/users/mock_user_manager.cc
index 26812e0a690d993a7bbc7a6c65a29d953142792a..3dd798a2423dce4238ebda70fc11aae5808e85de 100644
--- a/chrome/browser/chromeos/login/users/mock_user_manager.cc
+++ b/chrome/browser/chromeos/login/users/mock_user_manager.cc
@@ -13,7 +13,7 @@ namespace {
 class FakeTaskRunner : public base::TaskRunner {
  public:
   bool PostDelayedTask(const tracked_objects::Location& from_here,
-                       base::Closure task,
+                       base::OnceClosure task,
                        base::TimeDelta delay) override {
     std::move(task).Run();
     return true;