Prefer ScopedNestableTaskAllower over manual save/restore

base/message_loop_unittest.cc

 // Copyright (c) 2012 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 <vector>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/compiler_specific.h"
 #include "base/eintr_wrapper.h"
@@ skipping 967 matching lines @@
   EXPECT_EQ(order.Get(14), TaskItem(RECURSIVE, 1, true));
   EXPECT_EQ(order.Get(15), TaskItem(RECURSIVE, 1, false));
   EXPECT_EQ(order.Get(16), TaskItem(RECURSIVE, 3, true));
   EXPECT_EQ(order.Get(17), TaskItem(RECURSIVE, 3, false));
 }
 
 #endif  // defined(OS_WIN)
 
 void FuncThatPumps(TaskList* order, int cookie) {
   order->RecordStart(PUMPS, cookie);
-  bool old_state = MessageLoop::current()->NestableTasksAllowed();
-  MessageLoop::current()->SetNestableTasksAllowed(true);
-  MessageLoop::current()->RunAllPending();
-  MessageLoop::current()->SetNestableTasksAllowed(old_state);
+  {
+    MessageLoop::ScopedNestableTaskAllower allow(MessageLoop::current());
+    MessageLoop::current()->RunAllPending();
+  }
   order->RecordEnd(PUMPS, cookie);
 }
 
 // Tests that non nestable tasks run in FIFO if there are no nested loops.
 void RunTest_NonNestableWithNoNesting(
     MessageLoop::Type message_loop_type) {
   MessageLoop loop(message_loop_type);
 
   TaskList order;
 
@@ skipping 673 matching lines @@
       base::Bind(&DestructionObserverProbe::Run,
                  new DestructionObserverProbe(&task_destroyed,
                                               &destruction_observer_called)),
       kDelay);
   delete loop;
   EXPECT_TRUE(observer.task_destroyed_before_message_loop());
   // The task should have been destroyed when we deleted the loop.
   EXPECT_TRUE(task_destroyed);
   EXPECT_TRUE(destruction_observer_called);
 }