Make MessageLoopProxy::current() usable on threads that don't have MessageLoop.

base/thread_main_task_runner.h

+// 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.
+
+#ifndef BASE_THREAD_MAIN_TASK_RUNNER_H_
+#define BASE_THREAD_MAIN_TASK_RUNNER_H_
+#pragma once
+
+#include "base/base_export.h"
+#include "base/single_thread_task_runner.h"
+
+namespace base {
+
+// ThreadMainTaskRunner is a SignleThreadTaskRunner that is used for
+// the main task runner of a thread. There should never be more than
+// one object implementing this interface per thread. It provides
+// static current() method that returns the instance of this
+// insterface that corresponds to the current thread.

[Ami GONE FROM CHROMIUM, 2012/04/30 23:34:05]

typo: "insterface"

[Sergey Ulanov, 2012/05/01 00:34:54]

Done.

+class BASE_EXPORT ThreadMainTaskRunner : public SingleThreadTaskRunner {
+public:
+  // Gets the ThreadMainTaskRunner for the current thread.
+  static scoped_refptr<ThreadMainTaskRunner> current();
+
+   // Sets ThreadMainTaskRunner for the current thread. The caller
+   // must keep a reference to the task runner and call this method
+   // again with new_current=NULL before dropping that reference.
+   static void SetCurrent(ThreadMainTaskRunner* new_current);
+
+ protected:
+  virtual ~ThreadMainTaskRunner() {}
+};
+
+}  // namespace base
+
+#endif  // BASE_THREAD_MAIN_TASK_RUNNER_H_