Manual fixups for scoped_refptr conversion operator cleanup in mojo/

mojo/shell/task_runners.cc

 // Copyright 2013 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 "mojo/shell/task_runners.h"
 
 #include "base/threading/sequenced_worker_pool.h"
 
 namespace mojo {
 namespace shell {
 
 namespace {
 
 const size_t kMaxBlockingPoolThreads = 3;
 
 scoped_ptr<base::Thread> CreateIOThread(const char* name) {
   scoped_ptr<base::Thread> thread(new base::Thread(name));
   base::Thread::Options options;
   options.message_loop_type = base::MessageLoop::TYPE_IO;
   thread->StartWithOptions(options);
   return thread.Pass();
 }
 
 }  // namespace
 
-TaskRunners::TaskRunners(base::SingleThreadTaskRunner* shell_runner)
+TaskRunners::TaskRunners(
+    const scoped_refptr<base::SingleThreadTaskRunner>& shell_runner)
     : shell_runner_(shell_runner),
       io_thread_(CreateIOThread("io_thread")),
       blocking_pool_(new base::SequencedWorkerPool(kMaxBlockingPoolThreads,
                                                    "blocking_pool")) {
 }
 
 TaskRunners::~TaskRunners() {
   blocking_pool_->Shutdown();
 }
 
 }  // namespace shell
 }  // namespace mojo