Prefer ScopedNestableTaskAllower over manual save/restore

webkit/plugins/ppapi/ppb_flash_message_loop_impl.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 "webkit/plugins/ppapi/ppb_flash_message_loop_impl.h"
 
 #include "base/callback.h"
 #include "base/message_loop.h"
 #include "ppapi/c/pp_errors.h"
 
@@ skipping 70 matching lines @@
       callback.Run(PP_ERROR_FAILED);
     return PP_ERROR_FAILED;
   }
   state_->set_run_called();
   state_->set_run_callback(callback);
 
   // It is possible that the PPB_Flash_MessageLoop_Impl object has been
   // destroyed when the nested message loop exits.
   scoped_refptr<State> state_protector(state_);
 
-  bool old_value = MessageLoop::current()->NestableTasksAllowed();
-  MessageLoop::current()->SetNestableTasksAllowed(true);
+  MessageLoop::ScopedNestableTaskAllower allow(MessageLoop::current());
   MessageLoop::current()->Run();
 
   // Don't access data members of the class below.
 
-  MessageLoop::current()->SetNestableTasksAllowed(old_value);
   return state_protector->result();

[Ryan Sleevi, 2012/02/11 02:17:22]

Also here - state_protector->result() runs while nestable loops are still
allowed.

[jar (doing other things), 2012/02/11 03:24:38]

+1

Please put lines 91 and 92 into a local scope.

On 2012/02/11 02:17:22, Ryan Sleevi wrote:

[dhollowa, 2012/02/13 17:44:26]

Done.

 }
 
 void PPB_Flash_MessageLoop_Impl::InternalQuit(int32_t result) {
   if (!state_->run_called() || state_->quit_called())
     return;
   state_->set_quit_called();
   state_->set_result(result);
 
   MessageLoop::current()->QuitNow();
 
   if (!state_->run_callback().is_null())
     state_->run_callback().Run(result);
 }
 
 }  // namespace ppapi
 }  // namespace webkit